Electronic Modular Control Panel II+ (EMCP II+) Caterpillar

Illustration 1	g00442023
System Schematic For Starting Motor Relay (SMR)

Illustration 2	g00823794
Engine Relay Panel For 3412 MUI (ETR) (1) Starting Motor Magnetic Switch SMMS1 (ETR) (2) Starting Motor Magnetic Switch SMMS2 (ETR)

Illustration 3	g00823793
Engine Relay Panel for 3456 Engines (ETR) (1) Starting Motor Magnetic Switch 1 (SMMS1)

Illustration 4	g00800343
Engine Relay Panel For 3412 PEEC Engines (1) Starting Motor Magnetic Switch SMMS1 (ETR) (2) Starting Motor Magnetic Switch SMMS2 (ETR)

Illustration 5	g00800356
Engine Relay Panel For 3412 MUI Engines (ETS) (1) Starting Motor Magnetic Switch SMMS1 (ETS) (2) Starting Motor Magnetic Switch SMMS2 (ETS)

Test Procedure

Two starting motor magnetic switches (SMMS) are used in dual starting motor systems, one for each starting motor.

1. From beneath the control panel, disconnect DC connector number 2 from the control panel. DC connector number 2 is the left most connector when viewed from the front panel. From beneath the control panel use the 7X-1710 Cable Probes to measure the resistance between connector contact 6 (SMMS) and connector contact 11 (B-). The resistance should measure the following values.
   • 26 to 33 ohms for single starting motor systems

   • 13 to 17 ohms for dual starting motor systems

   If the resistance is NOT correct, replace the defective magnetic switch. If the resistance is correct, proceed to Step 2.

2. Disconnect the cable going from the pinion solenoid to the starting motor. Do this on both starting motors of a dual starting motor system.

3. Inside the Engine Relay Panel, at the SMMS, prepare to connect a DC voltmeter. The positive lead connects to wire 24 and the negative lead connects to wire 25. (If a second magnetic switch is tested in a dual starting motor system, then connect the negative lead to wire 26.)

   Note: The jumper wire of Step 4 energizes the starting motor magnetic switch.The jumper wire can remain connected for only ten seconds.

4. In the Engine Relay Panel, at the SMMS, temporarily connect a jumper wire from terminal 1 (B+) to terminal 4. Disconnect this wire immediately after the voltage is measured (no more than 10 seconds). The correct measurement changes from approximately 24 DCV to approximately 2 DCV.

If voltage is greater than 2.0 DCV, then replace the magnetic switch. If the switch passes the requirements of Step 1 and Step 4, it is functioning correctly. Reconnect the wires and cables that were removed in this procedure.