03DelcoRemy Diagnostic Manual130004222020

delcoremy.com Page 17 3-19. TEST PROCEDURE. NOTE Magnetic switch that does not close or drops out too soon can be caused by high resistance or open circuit in the control circuit. NOTE Leave the S lead disconnected to prevent engine from cranking during these tests. Connect 1. Digital voltmeter set on battery voltage scale to two small terminals on magnetic switch. If magnetic switch has only one small terminal, use switch bracket for other connection. Test 1. With key on, push start button. Listen for click that signifies magnetic switch closing. Note and record voltmeter reading V(13). 2. If magnetic switch closed (click detected or voltage at both large switch terminals) and voltage V(13) is within 1.0 volt (2.0 volts for 24-volt system) of battery voltage V(12), this circuit is okay. 3. If magnetic switch does not close and voltage V(13) is within 1.0 volt (2.0 volt for 24-volt system) of battery voltage V(12), replace magnetic switch and retest. 4. If voltage V(13) is more than 1.0 volt (2.0 volt for 24-volt system) below battery voltage, move the voltmeter lead on the magnetic switch ground to frame or motor ground terminal. With key on, push start button and read voltage V(14). If voltage V(14) is within 1.0 volt (2.0 volts for 24-volt system) of battery voltage, repair magnetic switch ground lead or connections. If not, replace voltmeter ground lead at magnetic switch ground terminal. 5. Repeat step 4, moving voltmeter plus lead to the following locations and measuring the specified voltages with the key on and the push-button depressed. If any voltage is not within 1.0 volt (2.0 volts for 24-volt system) of battery voltage, repair or replace the wire or component specified and retest: V(15)-wire between push-button and magnetic switch V(16) push-button V(17) wire between push-button and key switch V(18) key switch V(19) wire between key switch and solenoid BAT terminal 3-20. TEST COMPLETION. Remove voltmeter from vehicle. If all tests have been completed satisfactorily, reconnect lead to S terminal on starter solenoid so that engine can be started. PUSH BUTTON MAGNETIC SWITCH VOLTAGE (13) V(15) V(16) IGNITION BATTERY CABLE VOLTAGE (12) V(19) V(14) V(17) V(18) DP-1025 FIGURE 3-7. Magnetic Switch Circuit Test 3-21. STARTER REPLACEMENT DETERMINATION Up to this point, the batteries and starter wiring have been checked. The following additional checks should be made before considering starter replacement, and finally, the criteria for starter replacement, if necessary. 3-22. COLD WEATHER CRANKING. Starter circuits with a magnetic switch also can fail to hold during cold weather starting and low voltage, even though the switches and circuits tested okay at higher temperatures. This condition will sound as though the starter is failing to stay engaged with the engine. It is caused by the cold weather low voltage of the system releasing the electrical connection of the magnetic switch. To test for this condition, proceed as follows: Test CAUTION Large terminal studs on magnetic switch are at battery voltage. Engine should crank when jumper is connected. 1. With key switch on, press start button and have assistant clamp heavy battery jumper cable between two large studs on magnetic switch. Engine should crank. 2. Immediately remove jumper to stop engine cranking. 3. If engine starts with jumper in place, replace magnetic switch.