D7E Track-Type Tractor Hydraulic, HVAC, and Electrical Systems Caterpillar

Electrical Maintenance Guidelines

Usage:

D7E MDB

Electrical Maintenance Guidelines for the Power Train Electric Drive System and the Accessory Power System

During normal machine operation and for a short time after the machine is shutdown, the Power Train Electric Drive System contains hazardous levels of Alternating Current (AC) voltage and Direct Current (DC) voltage. The components and conductors that are used in the system are designed to provide a high degree of safety to operators and technicians during machine operation or when service is performed on one of the machine systems.

Each of the housings for the Power Train Electric Drive System components is grounded to the machine frame ground by the housing mount. The bus bars, the power transistors, the generator windings and the motor windings that are conducting electricity inside of the component housings are electrically isolated from the grounded housing.

The components that are used in operation of the Power Train Electric Drive System and the Accessory Power System are sealed in order to provide the electrical isolation and to prevent contamination from entering the components.

In the event that there is a short circuit to a component housing or a short circuit to the machine frame, the isolation of the system voltages from frame ground ensures there is no ground path for current flow back to the voltage source.

The component housings are connected to each other and to the machine frame by a "bonding" ground wiring system.

In addition to the bonding ground system, each of the individual electrical conductors that are used in the Power Train Electric Drive System and the Accessory Power System are surrounded by a grounded stainless steel sleeve or a grounded bronze sleeve. The sleeves for each conductor are mechanically connected to a grounded component housing at both ends of the conductor or at one end of the conductor.

Redundant grounding systems and the ability of the control modules to detect very small amounts of the “leakage” of voltage to frame ground ensure the safe operation of the Power Train Electric Drive System and the accessory Power System.

READ AND FOLLOW THESE PROCEDURES IN ORDER TO ENSURE THAT PERSONNEL THAT ARE TO PERFORM SERVICE OR MAINTENANCE ON THE MACHINE ELECTRICAL SYSTEMS OR THE MACHINE MECHANICAL SYSTEMS ARE ACTING IN A SAFE MANNER.

Note: When a service procedure must be performed immediately after machine shutdown, the following “Safe Shutdown Procedure” must be performed in order to verify that hazardous voltage is no longer present in the Power Train Electric Drive System or the Accessory Power System.

Note: When a service procedure must be performed after the machine has not been operated for a period of time, the “Hazardous Voltage Lamp Test” that is presented after the Safe Shutdown Procedure should be performed in order to verify that operation of the Hazardous Voltage Lamp is correct.

When the key start switch is turned to the OFF position after machine operation, some residual DC voltage is present in the system. The Electric Water Pump will continue to operate for a short period of time in order to "drain" the DC voltage down to a safe level. Normally, this should occur in less than five seconds, however, this could take as long as five minutes under some circumstances. The Hazardous Voltage Lamp will turn OFF when the voltage is at a safe level.

When possible, all service procedures should be performed when the Engine and the Generator are not operating. DO NOT PERFORM ANY TYPE OF PROCEDURE ON THE POWER TRAIN ELECTRIC DRIVE SYSTEM COMPONENTS OR THE ACCESSORY POWER TRAIN SYSTEM COMPONENTS WHEN THE ENGINE AND THE GENERATOR ARE IN OPERATION.

Note: If you are not sure which components are used in the Power Train Electric Drive System and the Accessory Power System, do not perform maintenance on the machine. Refer to the Systems Operation, "Power Train Electrical System" section of this manual in order to be able to identify the components that are involved.

When a test procedure, an adjustment procedure or procedure on the 24 volt electrical system does require the Engine and the Generator to be operating, certain safety guidelines must be followed. Refer to the following “Performing Maintenance Procedures With The Engine And Generator Operating” section for instructions.

Safe Shutdown Procedure for Electric Drive Tractors

When the machine is to be serviced after the Engine has been in operation, perform this Safe Shutdown Procedure in order to ensure that the residual voltage in the electrical power train systems and the accessory power systems are at a safe voltage level before any work is performed.

Note: The amber Hazardous Voltage Present Lamp monitors the voltage levels of the DC Power Bus voltage and the DC Accessory Power Bus voltage at all times. When hazardous voltage levels are present, the lamp is illuminated. When the key start switch is moved to the OFF position, the Hazardous Voltage Present Lamp will remain illuminated until the voltage levels in the DC system is at a safe level (50.0 VDC or less). The Electric Water Pump will continue to operate after key OFF for a short period of time in order to "drain" the DC voltage down to a safe level. Normally, the voltage should decrease to under 50.0 VDC in less than five seconds, however, this could take as long as five minutes under some circumstances. The Hazardous Voltage Lamp will turn OFF when the voltage is at a safe level. The Hazardous Voltage Present Lamp circuit will operate regardless of the state of the disconnect switch.

Turn the key start switch to the OFF position.

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Illustration 1	g01477573
The Ground Disconnect Switch and the Hazardous Voltage Present Lamp located under the access cover on the left fender of the machine. (1) Ground Disconnect Switch (2) Hazardous Voltage Present Lamp

Access the disconnect switch and the Hazardous Voltage Present Lamp that are located under the access cover on the left hand fender of the machine.
Observe the state of the amber Hazardous Voltage Present Lamp. If the lamp IS ILLUMINATED, do not perform any type of service on the machine. Wait until the lamp is NOT ILLUMINATED. Then, perform the lamp test in the next step.
In order to check the operation of the Hazardous Voltage Present Lamp, perform the following lamp test when the lamp is NOT ILLUMINATED. While observing the lamp, turn the disconnect switch to the OFF position and then turn the disconnect switch to the ON position.
When the disconnect switch is turned to the ON position, the amber Hazardous Voltage Present Lamp will illuminate briefly and then turn OFF. This indicates that the operation of the lamp circuit is correct and that the voltage level in the power train electrical system is at a safe level.
Once the operation of the Hazardous Voltage Present Lamp has been checked and the lamp operation is correct, the disconnect switch can be turned to the OFF position. The machine can now be serviced.
Note: If the Hazardous Voltage Present Lamp does not operate as expected, the Caterpillar Electronic Technician (Cat ET) Service Tool or the Instrument Cluster display must be used to monitor the voltage levels of the DC Power Bus and the DC Accessory Power Bus. The voltage levels for each bus circuit must be below 50.0 VDC before the machine can be serviced.
Note: When the machine is operating and a problem is detected in the Hazardous Voltage Present Lamp circuit, an error message will be activated on the Instrument Cluster. The Implement Control ECM will activate a CID 3242 diagnostic code in order to indicate the abnormal condition in the lamp circuit. When a diagnostic code is activated for the lamp circuit, refer to the Implement Electronic Control System, KENR5165 Service Manual. Perform the troubleshooting procedure for the active CID 3242 diagnostic code in order to correct the problem. The Caterpillar Electronic Technician (Cat ET) Service Tool or the Instrument Cluster display can be used to monitor the voltage levels of the DC Power Bus and the DC Accessory Power Bus. The voltage levels for each bus circuit must be below 50.0 VDC before the machine can be serviced.

Hazardous Voltage Present Lamp Test

Note: When an electrical service procedure must be performed, the “Hazardous Voltage Lamp Test” should be performed in order to verify that operation of the Hazardous Voltage Lamp is correct.

In order to check the operation of the Hazardous Voltage Present Lamp, perform the following lamp test when the Engine is OFF and the lamp is NOT ILLUMINATED.

Access the disconnect switch and the Hazardous Voltage Present Lamp that are located under the access cover on the left hand fender of the machine.
While observing the Hazardous Voltage Present Lamp, turn the disconnect switch to the OFF position and then turn the disconnect switch to the ON position.
When the disconnect switch is turned to the ON position, the amber Hazardous Voltage Present Lamp will illuminate briefly and then turn OFF. This indicates that the operation of the lamp circuit is correct and that the voltage level in the medium voltage system is at a safe level.

Incorrect operation of the Hazardous Voltage Present Lamp can be indicated by the following lamp conditions:

When the engine is running, the Hazardous Voltage Present Lamp is NOT ILLUMINATED.
When the key start switch is in the OFF position, the Hazardous Voltage Present Lamp IS ILLUMINATED and DOES NOT TURN OFF for a period of more than ten seconds.
When the key start switch is in the OFF position and the lamp test is performed (disconnect switch is cycled from OFF to ON), the Hazardous Voltage Present Lamp does NOT ILLUMINATE briefly and then turn OFF.

If any of these Hazardous Voltage Present Lamp conditions are present, use the Caterpillar Electronic Technician (Cat ET) Service Tool or use the Instrument Cluster to monitor the voltage levels of the DC Power Bus and the DC Accessory Bus systems. The voltage levels of these systems must be below 50.0 VDC before the machine can be serviced.

For troubleshooting the Hazardous Voltage Present Lamp circuit, refer to the Implement Electronic Control System, KENR5165 Service Manual. Perform the troubleshooting procedures for the CID 3242 diagnostic code.

Performing Machine Maintenance with the Key Start Switch ON and the Engine OFF

DC VOLTAGE IS PRESENT IN THE POWER TRAIN ELECTRIC DRIVE SYSTEM AND THE ACCESSORY POWER SYSTEM FOR A SHORT PERIOD AFTER MACHINE SHUTDOWN.

WHEN THE MACHINE CONTROL 24 VOLT ELECTRICAL SYSTEM IS SERVICED, FOLLOW THE SAFE SHUTDOWN PROCEDURE THAT IS OUTLINED ABOVE. VERIFY THAT THE POWER TRAIN VOLTAGES ARE AT A SAFE LEVEL BEFORE SERVICE IS PERFORMED ON THE 24 VOLT ELECTRICAL SYSTEM.

When a procedure requires that the key start switch and the disconnect switch be moved to the ON position, DO NOT START THE ENGINE.

When the key start switch and the disconnect switch are in the ON position, system battery power will be supplied to all of the control modules and to all of the components in the 24 volt machine control electrical system.

Performing Maintenance Procedures with the Engine and the Generator Operating

Daily maintenance procedures and service maintenance for the mechanical systems, the hydraulic systems and low voltage machine control electrical system can be performed when the Engine and the Generator are in operation.

HAZARDOUS VOLTAGE LEVELS ARE PRESENT WHEN THE ENGINE AND THE GENERATOR ARE OPERATING.

DO NOT PERFORM ELECTRICAL MAINTENANCE SERVICE ON THE ORANGE CLAD HAZARDOUS VOLTAGE CONDUCTORS, THE POWER TRAIN COMPONENTS OR THE ACCESSORY POWER SYSTEM COMPONENTS WHEN THE ENGINE IS RUNNING.

AVOID CONTACT WITH THE POWER TRAIN SYSTEM COMPONENTS AND THE ACCESSORY SYSTEM COMPONENTS INCLUDING THE GENERATOR, THE ELECTRIC DRIVE PROPULSION MODULE, THE POWER INVERTER, THE ELECTRIC WATER PUMP SYSTEM, THE ELECTRIC HVAC SYSTEM AND THE ORANGE CLAD ELECTRICAL CONDUCTORS WHEN THE ENGINE AND GENERATOR ARE OPERATING.

The following practices must be followed when a maintenance procedure is performed when the Engine and Generator are in operation.

The first rule that anyone working on any power system must follow is: "IF IT IS ENERGIZED, DO NOT TOUCH IT". When the Engine and the Generator are operating and work is being performed in close proximity to the electrical power train components or the accessory power components, avoid all contact with these components. Do not use the Power Train Electric Drive System components or the Accessory Power System components for hand holds. Do not climb on the components. Do not lay on the components or use the components for steps. Do not use the components for bracing or support.
The grounding bond wires and the conductor shield grounding wires must be connected to the component housing connection points at all times during machine operation.
Any time the machine is to be cleaned using a power wash system, it is recommended that the engine is OFF, the key start switch is in the OFF position and the disconnect switch is in the OFF position. Avoid direct contact or close operation of the spray wand with the electrical components. Avoid direct power spray on all electrical components, connectors and seals at all times.
If the machine must be washed with the Engine and Generator in operation, use good judgement when cleaning around or close to the electrical components. Maintain the largest possible distance between the spray wand and the surface that is being cleaned. Avoid direct contact or close operation of the spray wand with the electrical components. Avoid direct power spray on all electrical components, connectors and seals at all times.
Installation or removal of test equipment or measuring equipment must be done after the engine is turned OFF and the Safe Shutdown Procedure has been performed.
When a welding procedure is to be performed on the machine, it is recommended that the engine is OFF, the key start switch is in the OFF position and the disconnect switch is in the OFF position. If the welding procedure must be performed with the Engine and the Generator in operation, safely place the welder ground connection as close to the weld area as possible.

Related Service Manuals

The diagnostics for the Transmission Chassis ECM Electronic Power Train Control System can be accessed through the Instrument Cluster Display or the Caterpillar Electronic Technician (Cat ET). Troubleshooting the system requires additional information from the Service Manual for the machine. The following list of references should be used to troubleshoot the systems of the machine:

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Table 1
Related Service Manuals
Title	Form Number
D7E Track Type Tractor Service Manual	KENR5156
D7E Track-Type Tractor Electrical and Hydraulic Power Train Systems	KENR5160
Monitoring System	KENR8246
C9 Engine Troubleshooting	RENR9312
Additional References
Electrical System Schematic	KENR5167
Hydraulic System Schematic	KENR5161
Cooling System Schematic	KENR5176

Electrical System Troubleshooting

As a reference, simplified electrical system connection schematics for the Machine ECM, the Generator ECM, the Motor ECM, the Power Inverter and the Accessory Power Converter are included in the back of this manual.

The schematics illustrate the end connections for the control modules and the system component circuits. The schematics do not illustrate the machine wiring harness connectors. The schematics do not illustrate the circuits of machine electrical systems that are not associated with the power train components or the accessory power components.

When troubleshooting any part of the machine electrical system, the machine Electrical System Schematic in the Service Manual for your machine should be used along with this manual. The Electrical System Schematic will illustrate the complete circuit information for all of the machine electrical systems.

Unexpected Power Train Shutdown

Some of the electrical system conditions that will cause an ECM to activate a Diagnostic Code (CID) or an Event Code (EID) are severe enough to result in the Machine ECM immediately disabling the Power Train System. When this occurs, the brakes will be applied and the machine will not be allowed to move.

A fault reset should be attempted in order to clear the CID or the EID that caused the problem. If the condition that caused the activation of the CID or the EID is no longer present, normal machine operation can resume. If the fault condition is still present, the CID or the EID will be activated again. The Power Train System will remain disabled.

Many of the Diagnostic Codes and Events that can be activated by an ECM will automatically reset once the condition that caused the fault is no longer present.

Some of the Diagnostic Codes and Events that can be activated by an ECM require one of two different reset procedures to be performed in order to reset the active fault when the condition that caused the fault to be activated is no longer present.

The Instrument Cluster Display will alert the operator or the technician which of the following two reset procedures to perform in order to reset a specific fault when activated.

The following "Key Cycle" fault reset procedure will reset the majority of the active system Diagnostic Codes and active Events when the condition that caused the fault activation is no longer present.

Stop the machine if not already stopped.
With the engine operating, move the FNR switch to the NEUTRAL position.
Cycle the parking brake by engaging the Parking Brake. Then, disengage the parking brake. Engage the parking brake again.
Check the status of the active CID or the active EID.
If the condition that caused the CID or the EID to activate is no longer present, the fault will reset and will not be re-activated. Resume normal machine operation.
If the condition that caused the CID or the EID to activate is still present, the fault will be re-activated. Refer to the troubleshooting section of this manual that covers the specific Diagnostic Code or Event Code that is active. Follow the troubleshooting procedure in order to isolate the condition that is causing the problem.

Some Diagnostic Codes and Events that can be activated by an ECM require that the machine to be shut down in order to reset. The following reset procedure should be followed.

With the engine operating, move the FNR switch to the NEUTRAL position.
Engage the parking brake.
Turn the key start switch to the OFF position.
Wait a minimum of 2 minutes, then start the engine.
Check the status of the active CID or the active EID.
If the condition that caused the CID or the EID to activate is no longer present, the fault will reset and will not be re-activated. Resume normal machine operation.
If the condition that caused the CID or the EID to activate is still present, the fault will be re-activated. Refer to the troubleshooting section of this manual that covers the specific Diagnostic Code or Event Code that is active. Follow the troubleshooting procedure in order to isolate the condition that is causing the problem.

During machine operation, if the Machine ECM detects certain abnormal machine or circuit conditions in the steering system or the power train system, a software driven "Limp Home Mode" will be available that will allow limited machine operation. The Limp Home Mode is only available when certain power train faults or conditions are detected.

For a listing of the conditions that will allow for activation of the Limp Home Mode and for more information, refer to the Systems Operation, "Features" section of this manual under the "Limp Home Mode" title.

Basic Troubleshooting Practice

Poor connections can often be the cause of a problem in an electrical circuit. When a problem is suspected to exist in a particular circuit, examine the machine wiring harness connectors that are used in the circuit. Verify that each of the connection points in the circuit are clean, dry and in good condition. If the connections are not in good condition, permanent electrical problems or intermittent electrical problems can result. Check that the wires are securely terminated in the pin or socket. Ensure that the pin or socket is seated correctly and locked in the connector body. Ensure that all of the connections in the suspect circuit are in good condition before other tests are performed.

When a troubleshooting procedure instructs you to “REPAIR THE HARNESS OR REPLACE THE HARNESS”, use the Electrical System Schematic in the Service Manual of the machine to investigate a circuit. Perform resistance checks between the harness connectors in a circuit in order to locate harness failures. Always check the ground circuit at the machine harness connector for the components.

For machine ground circuits, less than 5 ohms of resistance is required between the ground contacts of a connector and the frame ground. Excessive ground resistance that is greater than 5 ohms can cause an incorrect diagnosis of the system.

For ECM return circuits (ECM ground), resistance checks should be made between the circuit connections and the ECM harness connector return contact. Resistance checks that are made between the ECM return circuits and frame ground may register more than five ohms of resistance due to internal impedance in the ECM circuits.

When checking the continuity of an individual circuit, a resistance measurement of more than 5000 ohms will indicate an open in a conductor or an open in a connector. When a resistance measurement to check continuity in a circuit measures more than 5 ohms and less than 5000 ohms, this could be an indication of a connection point that is not completely open. The circuit may contain a connection that is corroded or loose.

When checking an individual circuit for a short circuit to another circuit or to a ground source (frame ground or a ground circuit), the circuit that is being checked must be completely disconnected from all of the other components and circuits. Disconnect the suspect circuit that is to be checked from the control module, the component and any other switches or sensors that may be used in the circuit.

A resistance reading of at least 5000 ohms is the suggested limit for determining if a circuit is shorted to another circuit or ground source. A resistance measurement of less than 5000 ohms can indicate that there could be a "leakage" of voltage or current between the two circuits that are being measured when in operation. In some instances, a resistance measurement of less than 5000 ohms may not always indicate a short circuit. The technician should use their own knowledge and experience when determining if two circuits are shorted to each other or if a circuit is shorted to ground.

ECM Pull Up Resisters

In order to aid in diagnostics of certain types of electrical circuits that are controlled by the ECM, an internal "pull up resister" is internally connected Between ECM switch and sensor signal input circuits and an above normal voltage source.

During normal operation, the switch or sensor signal will hold the circuit low or at a certain signal amplitude, however, circuit conditions such as a loss of power to the component, a disconnection or an open circuit will allow the circuit voltage to be pulled high through the ECM pull up resister. This will result in an above normal voltage condition at the ECM contact. As a result, the ECM will activate an FMI 03 (voltage above normal) diagnostic code for the affected circuit.

The types of ECM input circuits that have pull up voltage present are:

Pulse Width Modulated (PWM) sensor input circuits
Switch to ground switch input circuits
Active analog (voltage) input signal circuits
Passive analog (resistance) input signal circuits

The ECM pull up resister voltage should always be considered when troubleshooting one of the circuit types that are listed.

ECM Pull Down Resisters

In order to aid in diagnostics of electrical circuits that are controlled by the ECM, an internal "pull down resister" is connected between the ECM switch to battery type input circuits and an ECM ground circuit.

During normal operation, the closed switch contacts that are connected to a voltage source will hold the circuit high. When circuit conditions such as open switch contacts, a loss of power to the switch supply voltage, a disconnection in the switch circuit or an open circuit will allow the circuit to be pulled to ground potential through the ECM pull down resister. This will result in a below normal voltage condition at the ECM contact. As a result, the ECM will activate an FMI 04 (voltage below normal) diagnostic code for the affected circuit.

The ECM pull down resister should always be considered when troubleshooting a switch to battery type of input circuit.

Machine Power Distribution (Fuses, Circuit Breakers and Relays)

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Illustration 2	g01437552
Fuse Panel

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Illustration 3	g01437895
Fuse Panel fuse, circuit breaker and relay assignments (F = Fuse, R = Relay, CB = Circuit Breaker)

The fuse panel on the D7E Track Type Tractor is located under the access panel on the lower right side of the cab.

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Illustration 4	g01456254
System voltage supplies to the fuse panel

Unswitched "+" battery system power is supplied to the fuse panel from the bus bar that is connected to the supply side contact of the Main Relay. Switched "+" battery system power is supplied to the fuse panel from the bus bar that is connected to the switched side contact of the Main Relay.

The Main Relay is located on the right hand side of the fuse panel.

The following table shows the component assignments, the power circuits, the circuit description and the connector color that the power circuits connect to the fuse panel.

Note: Refer to the complete Machine Electrical System Schematic for complete power circuit information for fuse panel circuits.

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Table 2
Fuse Panel Component Assignments
Component (Amps)	Power Circuit	Switched/Unswitched Power	Circuit Description	Fuse Panel Connector Color (Contact)
Fuse 1 (15A)	186-RD(Red)	Unswitched	12V 15A Converter Power	Brown (A)
Fuse 2 (10A)	129-BU(Blue)	Switched	Machine Security System	Blue (E)
Fuse 3 (15A)	110-RD(Red)	Unswitched	12V 20 Amp Converter	Yellow (D)
Fuse 4 (15A)	184-BU(Blue)	Switched	Accugrade Components	Blue (D)
Fuse 5 (10A)	To Rear Floods Relay	Switched	Rear Flood Lamps
Fuse 7 (10A)	116-BR(Brown)	Switched	Accessory Power Converter	Blue (F)
Fuse 8 (15A)	114-RD(Red)	Unswitched	Horns	Blue (C)
Fuse 9 (15A)	104-RD(Red)	Unswitched	Accessory Power Converter HV Lamp	Yellow (E)
Fuse 10 (10A)	176-OR(Orange)	Switched	Ripper / Winch Control	Blue (G)
Fuse 11 (10A)	130-GN(Green)	Switched	Rear ROPS Flood Lamps Switch	Brown (E)
Fuse 12 (10A)	119-PK(Pink)	Switched	Product Link Switch	Brown (G)
Fuse 13 (10A)	131-BR(Brown)	Switched	Ripper Flood Lamp	Brown (H)
Fuse 14 (15A)	113-RD(Red)	Unswitched	Custom Accessories Relay	Yellow (C)
Fuse 15 (10A)	133-RD(Red)	Unswitched	Front Flood Lamps Switch	Yellow (B)
Fuse 16 (10A)	127-OR(Orange)	Switched	12V Converter Power	Yellow (F)
Fuse 17 (10A)	134-YL(Yellow)	Switched	A Post and Side Flood Lamps	Yellow (G)
Fuse 18 (15A)	150-RD(Red)	Unswitched	Engine ECM	Green (D, E)
Fuse 19 (15A)	160-RD(Red)	Unswitched	Generator ECM	Green (C, F)
Fuse 20 (15A)	170-RD(Red)	Unswitched	Motor ECM	Green (B, G)
Fuse 21 (15A)	197-RD(Red)	Unswitched	Implement ECM	Green (A, H)
Fuse 22 (10A)	To Prelube Motor Relay	Switched	Prelube Motor
Fuse 23 (10A)	117-YL(Yellow)	Switched	Instrument Cluster (Key Switch ON)	Orange (C)
Fuse 24 (10A)	Not Used	Switched	Power Train Wake Up	Orange (A)
Fuse 25 (15A)	A537-PK(Pink)	Switched	Seat Compressor Switch	Orange (B)
Fuse 26 (10A)	105-RD(Red)	Unswitched	Key Start Switch	Orange (H)
Fuse 27 (10A)	145-RD(Red)	Unswitched	Instrument Cluster	Orange (D)
Fuse 28 (15A)	195-YL(Yellow)	Switched	Park Brake Switch	Red (G)
Fuse 29 (10A)	198-RD(Red)	Unswitched	Service Brake Switch	Orange (E)
Fuse 30 (15A)	174-PK(Pink)	Switched	Custom Auxiliary Switch Connector	Red (E)
Fuse 31 (10A)	A101-GN(Green)	Switched	Accugrade Power Module 2	Red (F)
Fuse 32 (15A)	107-RD(Red)	Unswitched	Power Inverter	Black (A)
Fuse 33 (15A)	104-RD(Red)	Unswitched	Accessory Power Inverter	Black (B)
Fuse 34 (15A)	106-RD(Red)	Unswitched	Product Link Module	Red (B)
Fuse 35 (15A)	140-RD(Red)	Unswitched	Machine ECM	Red (A, H)
Circuit Breaker 1 (15A)	108-BU(Blue)	Switched	Wiper Motors	Brown (F)
Circuit Breaker 2 (20A)	To Condenser Motor Relay	Unswitched	Condenser Motor
Circuit Breaker 3 (20A)	To Blower Motor Relays	Unswitched	Blower Motor
Circuit Breaker 4 (15A)	124-GN(Green)	Unswitched	HVAC Control Panel	Gray (G)
Relay 2	515-GY(Grey)	Switched	Blower Motor High Speed	Gray (C)
Relay 4	608-GN(Green)	Switched	Rear Flood Lamps	Brown (C)
Relay 5	C557-OR(Orange)	Switched	Condenser Motor	Gray (F)
Relay 6	Not Used	Switched	Blower Motor Medium High Speed	Gray (A)
Relay 7	F705-PK(Pink)	Switched	Prelube Motor	Red (C)

Cab Bulkhead Connectors

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Illustration 5	g01438166
Two cab bulkhead 70 contact connectors that pass many of the Machine ECM and Implement ECM circuits through the cab wall (1) CH-C10 Upper 70 contact connector (Implement ECM circuits) (2) CH-C2 Lower 70 contact connector (Machine ECM circuits)

Most of the Machine ECM circuits and the Implement ECM circuits that are for chassis mounted components pass through the lower right hand cab wall in two 70 contact bulkhead connectors.

The lower CH-C2 bulkhead connector connects a large number of circuits from the "CH" machine wiring harness that is outside of the cab to the "C-C1" harness connector for Machine ECM circuits inside of the cab.

The upper CH-C10 bulkhead connector connects a large number of circuits from the "CH" machine wiring harness that is outside of the cab to the "RH-C6" harness connector for the Implement ECM circuits inside of the cab.

When troubleshooting an ECM circuit for a component that is located outside of the cab, the bulkhead connectors provide a good check point in a circuit that will help to isolate the location of the problem.

Disconnect the bulkhead connector on the outside of the cab. At the disconnected bulkhead connector, check the suspect circuit for short circuits, open circuits or poor connections at the appropriate connector contacts. This will help to determine whether the problem is in the chassis section of the circuit or if the problem is in the cab section of the circuit.

The lower bulkhead connector is used for Machine ECM circuits and the upper bulkhead connector is used for Implement ECM circuits.

The following illustrations show the connector contacts and the circuit assignments for the upper 70 contact bulkhead connector and the lower 70 contact bulkhead connector for the chassis CH machine wiring harness.

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