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.
- 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.
- 26 to 33 ohms for single starting motor systems
- Disconnect the cable going from the pinion solenoid to the starting motor. Do this on both starting motors of a dual starting motor system.
- 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.
- 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.