Control Circuit Test

Starting System Components:

The starter control circuit has:
- Starter solenoid
- Starter relay
- Transmission range sensor, or Park/Neutral Position switch with automatic transmissions
- Clutch Pedal Position Switch with manual transmissions
- Ignition switch
- Battery
- All related wiring and connections

CAUTION: Before performing any starter tests, the ignition and fuel systems must be disabled.

- To disable ignition and fuel systems, disconnect the Automatic Shutdown Relay (ASD). The ASD relay is located in the in the Power Distribution Center (PDC). Refer to the PDC cover for the proper relay location.

Starter Relay:

WARNING: CHECK TO ENSURE THAT THE TRANSMISSION IS IN THE PARK POSITION WITH THE PARKING BRAKE APPLIED.

STARTER SOLENOID TEST
1. Verify battery condition. Battery must be in good condition with a full charge before performing any starter tests. Refer to Battery Tests.
2. Perform Starter Solenoid test BEFORE performing the starter relay test.
3. Raise the vehicle.
4. Perform a visual inspection of the starter/ starter solenoid for corrosion, loose connections or faulty wiring.
5. Lower the vehicle.
6. Locate and remove the starter relay from the Power Distribution Center (PDC). Refer to the PDC label for relay identification and location.
7. Connect a remote starter switch or a jumper wire between the remote battery positive post and terminal 87 of the starter relay connector.
a. If engine cranks, starter/starter solenoid is good. Go to the Starter Relay Test.
b. If engine does not crank or solenoid chatters, check wiring and connectors from starter relay to starter solenoid for loose or corroded connections. Particularly at starter terminals.
c. Repeat test. If engine still fails to crank properly, trouble is within starter or starter mounted solenoid, and replace starter.

WARNING: CHECK TO ENSURE THAT THE TRANSMISSION IS IN THE PARK POSITION/NEUTRAL WITH THE PARKING BRAKE APPLIED.

STARTER RELAY TEST
The starter relay is located in the Power Distribution Center (PDC) in the engine compartment. Refer to the PDC label for relay identification and location.

Remove the starter relay from the PDC as described -- to perform the following tests:
1. A relay in the de-energized position should have continuity between terminals 87A and 30, and no continuity between terminals 87 and 30. If OK, go to Step 2. If not OK, replace the faulty relay.
2. Resistance between terminals 85 and 86 (electromagnet) should be 75 ± 5 ohms. If OK, go to Step 3. If not OK, replace the faulty relay.
3. Connect a battery B+ lead to terminals 86 and a ground lead to terminal 85 to energize the relay. The relay should click. Also test for continuity between terminals 30 and 87, and no continuity between terminals 87A and 30. If OK, refer to Relay Circuit Test procedure. If not OK, replace the faulty relay.

STARTER RELAY CIRCUIT TEST
1. The relay common feed terminal cavity (30) is connected to battery Voltage and should be hot at all times. If OK, go to Step 2. If not OK, repair the open circuit to the PDC fuse as required.
2. The relay normally closed terminal (87A) is connected to terminal 30 in the de-energized position, but is not used for this application. Go to Step 3.
3. The relay normally open terminal (87) is connected to the common feed terminal (30) in the energized position. This terminal supplies battery Voltage to the starter solenoid field coils. There should be continuity between the cavity for relay terminal 87 and the starter solenoid terminal at all times. If OK, go to Step 4. If not OK, repair the open circuit to the starter solenoid as required.
4. The coil battery terminal (86) is connected to the electromagnet in the relay. It is energized when the ignition switch is held in the Start position. On vehicles with a manual transmission, the clutch pedal must be fully depressed for this test. Check for battery Voltage at the cavity for relay terminal 86 with the ignition switch in the Start position, and no Voltage when the ignition switch is released to the On position. If OK, go to Step 5. If not OK with an automatic transmission, check for an open or short circuit to the ignition switch and repair, if required. If the circuit to the ignition switch is OK, see the Ignition Switch Test. If not OK with a manual transmission, check the circuit between the relay and the clutch pedal position switch for an open or a short. If the circuit is OK, see the Clutch Pedal Position Switch Test.
5. The coil ground terminal (85) is connected to the electromagnet in the relay. On vehicles with an automatic transmission, it is grounded through the park/neutral position switch only when the gearshift selector lever is in the Park or Neutral positions. On vehicles with a manual transmission, it is grounded at all times. Check for continuity to ground at the cavity for relay terminal 85. If not OK with an automatic transmission, check for an open or short circuit to the park/neutral position switch and repair, if required. If the circuit is OK, see the Park/Neutral Position Switch Test procedure in this section. If not OK with a manual transmission, repair the circuit to ground as required.

SAFETY SWITCHES
Test the applicable switches:
- Clutch Pedal Position Switch
- Park/Neutral Position Switch

IGNITION SWITCH
After testing starter solenoid and relay, test ignition switch and wiring. Check wiring for opens, or shorts, and all connectors for loose terminals and corrosion.

BATTERY
Check battery state of charge and condition.

RELATED WIRING AND CONNECTORS
Check all related wiring and connectors.