The following information is a guide to reading the tables on the back of the Electrical Schematic.
- The component location table uses white circles to mark the locations in the profile of the vehicle and in the area views. Alphabetical letters in the machine location column indicate a general area of the vehicle. Refer to the corresponding footnote at the end of the table for a description of the location.
- The harness connector location table uses white circles to mark the locations in the general view and in the area views. Alphabetical letters in the machine location column indicate a general area of the vehicle. Refer to the corresponding footnote at the end of the table for a description of the location.
The following illustrations serve as guides to locating electrical components that are associated with the 777G brakes.
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| Illustration 1 | g02175538 |
Left side and rear of truck (54) Brake filter bypass switch (57) Front brake solenoid (59) Engine speed sensor (60) Right brake ARC/TCS proportional solenoid (61) Left brake ARC/TCS proportional solenoid (62) ARC/TCS enable solenoid | |
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| Illustration 2 | g02192774 |
Right side and front of truck (1-36) 24V panel (40-51) 24V Relays (56) Right wheel speed sensor (58) Park brake solenoid | |
Fuses, Circuit Breakers, and Relays - Replace/Reset
The fuse and relay panels are located in the operator compartment behind the companion seat, refer to figure 3
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| Illustration 3 | g02157900 |
Fuse and relay panels (A) 12V panel (B) 24V panel | |
Fuses
Fuses protect the electrical components from damage caused by overloaded electrical circuits. Replace a fuse if the element separates. If the fuse of a particular electrical system requires frequent replacement, check the electrical circuit. Repair the electrical circuit, if necessary.
Note: Always replace a fuse with the proper type and capacity of fuse. Otherwise, electrical damage could result.
12V Panel
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| Illustration 4 | g02157781 |
12V panel (1) 12V power port (Dash panel) (15A) (2) 12V power port (Rear panel) (15A) (3) Cigar lighter (15A) (4) Communication radio (15A) (5) Entertainment radio (15A) (6) MineStar (10A) | |
24V Panel
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| Illustration 5 | g02157707 |
24V panel (7) 24V to 12V converter (20A) (8) Stop lamps (15A) (9) Brake ECM (15A) (10) Instrument cluster (10A) (11) Product link (15A) (12) Chassis ECM (15A) (13) Horn (10A) (14) Directional signal/hazard lights (10A) (15) VIMS (10A) (16) Keyswitch (10A) (17) Right high beam lights (15A) (18) Left high beam lights (15A) (19) Work lights (15A) (20) Instrument panel backlight (10A) (21) Custom light (Pre-wired) (15A) (22) Window wipers (5A) (23) Custom light (Pre-wired) (15A) (24) Air precleaner (10A) (25) Suspension seat (15A) (26) Reverse (Rear) lights (10A) (27) Window washer (10A) (28) Auto lube (10A) (29) Sensor power (15A) (30) WAVS (Camera system) (15A) (31) Secondary steering (10A) (32) ECM (10A) (33) Heated mirror (15A) (34) HVAC (20A) (35) Tire pressure monitor (10A) (36) Power window (20A circuit breaker) | |
Circuit Breakers
Push in the button to reset the circuit breaker. If the electrical system is working properly, the button will remain depressed. If the button does not remain depressed, check the appropriate electrical circuit. Repair the electrical circuit, if necessary.
Note: The circuit breakers for the low beam headlights are automatic reset circuit breakers.
| Power Window (36) - 20 Amp (Refer to Illustration 5) |
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| Illustration 6 | g02157914 |
Ground level control box | |
| Alternator (37) - 90 Amp |
| Main (38) - 90 Amp |
| Engine ECM (39) - 15 Amp |
Relays
A relay is an electrical switch that opens and closes under the control of another electrical circuit.
12V Panel Relays
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| Illustration 7 | g02157807 |
12V panel relays (40) Left low beam lights (41) Right low beam lights (42) Right high beam lights (43) Left high beam lights (44) Work lights | |
24V Panel Relays
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| Illustration 8 | g02157805 |
24V panel relays (45) Reverse (Rear) lights (46) Air conditioner (47) Stop lamps (48) Intermittent wiper (49) Delayed engine shutdown override (50) Auto lube (51) Secondary steering (52) Heated mirror | |
Brake ECM
The brake ECM is located in the cab, behind the operators seat.
Brake Oil Temperature Sensor
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| Illustration 9 | g02175522 |
Brake oil temperature sensor location | |
The brake oil temperature sensor (53) is located on the right side of the truck, by the rear wheels.
Brake Filter Bypass Switch
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| Illustration 10 | g02175554 |
Brake filter bypass switch location | |
The brake filter bypass switch (54) is located on the brake filter boss.
Left Rear Wheel Speed Sensor
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| Illustration 11 | g02175556 |
Left rear wheel speed sensor location | |
The left rear wheel speed sensor (55) is located at the left rear wheel.
Right Rear Wheel Speed Sensor
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| Illustration 12 | g02175562 |
Right rear wheel speed sensor location | |
The right rear wheel speed sensor (56) is located at the right rear wheel.
Front Service Brake Solenoid
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| Illustration 13 | g02175565 |
Front brake solenoid location | |
The front service brake solenoid (57) is located inside the left main rail by the torque converter.
Park Brake Solenoid
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| Illustration 14 | g03645110 |
Park brake solenoid location | |
The park brake solenoid (58) , is installed on the parking brake valve, which is located inside the left main rail. The brake accumulator purge solenoid (58A) , is also installed on the parking brake valve.
Service Brake Pedal Position Sensor
The service brake pedal position sensor is located at the cab floor, on the left side of the service brake.
Engine Speed Sensor
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| Illustration 15 | g02175572 |
Engine speed sensor location | |
The engine speed sensor (59) is located on the left side of the engine, toward the front of the engine.
ARC/TCS Solenoids
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| Illustration 16 | g02175576 |
ARC/TCS solenoid locations (Right brake ARC/TCS proportional solenoid ) 60 (Left brake ARC/TCS proportional solenoid ) 61 (ARC/TCS enable solenoid) 62 | |
Right Brake ARC/TCS Proportional Solenoid
The right brake ARC/TCS proportional solenoid (60) is located on the forward, center of the rear tail casting.
Left Brake ARC/TCS Proportional Solenoid
The left brake ARC/TCS proportional solenoid (61) is located on the forward, center of the rear tail casting.
ARC/TCS Enable Solenoid
The ARC/TCS enable solenoid (62) is located on the forward, center of the rear tail casting.
Service Tool Connectors
The 777G has two Cat ® ET service tool connectors. One is accessible from the ground and is located at the front of the truck. The other is located in the cab, on the side of the fuse panel.