The Ignition Relay is controlled by the ignition switch. When the ignition switch in the run, or crank position, ignition voltage is supplied to the relay coil which allows voltage through the relay switch contacts to the engine control module (ECM).

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

Scan Tool Reference

Engine Control Module Scan Tool Information

Cycle the ignition from OFF to ON. You should hear and feel an audible click from the ignition relay. Repeat as necessary in order to verify ignition relay operation.

1. Ignition OFF, disconnect the ignition relay.
2. Test for less than 5 ohms between the ground circuit terminal 85 and ground.

⇒	If greater than the specified range, repair the ground circuit for an open/high resistance.

3. Connect a test lamp between the relay coil control circuit terminal 86 and ground.
4. Cycle the ignition ON and OFF. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the ignition switch.

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ignition switch.

5. Test for B+ between the relay switch voltage circuit terminal 30 and ground.

⇒	If less than the specified range, repair the relay switch voltage circuit for an open/high resistance.

6. Install a 15A fused jumper wire between the relay switch voltage circuit terminal 30, and the relay switch supply circuit terminal 87. Attempt to start the engine. The engine should start and idle.

⇒	If the engine does not start and idle, test the run/crank relay signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

7. If all circuits test normal, test or replace the ignition relay.

1. Ignition OFF, disconnect the ignition relay.
2. Test for 70-110 ohms between terminals 85 and 86.

⇒	If not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not within the specified range, replace the relay.

4. Install a 20A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.

⇒	If greater than the specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.