Main Relay Harness Test

1. Keep the ignition switch in the OFF position.
2. Disconnect the main relay electrical connector.
3. Check for continuity between the BLACK wire, Pin (2), in the connector and body ground. There should be continuity.

a. If there is no continuity, repair open in BLK wire.
b. If there is continuity, go to step 4.

Fig. 55 Main Relay Harness Test (pins 2 and 1):

Fig. 56 Main Relay Harness Test (pins 2 and 5):

4. Attach the positive probe of the voltmeter to the YELLOW/BLUE wire, pin (1), and the negative probe to the BLACK wire, pin (2).

a. Battery should be available.
b. If there is no voltage, check the wiring between the battery and the main relay as well as the EFI ECU fuse (10A) in the under-hood relay box.

5. Attach the positive probe of the voltmeter to the BLACK/YELLOW wire, pin (5), and the negative probe to the BLACK wire, pin (2).
6. Turn the ignition switch ON.

a. Battery voltage should be available.
b. If there is no voltage, check the wiring from the ignition switch and the main relay as well as the #12 (10A) fuse.

Fig. 57 Main Relay Harness Test (pins 2 and 4):

Fig. 58 Main Relay Harness Jumper Wire Test For Fuel Pump:

7. Attach the positive probe of the voltmeter to the BLUE/RED wire, pin (4), and the negative probe to the BLACK wire, pin (2).
8. Turn the ignition switch to the start position.

a. Battery voltage should be available.
b. If there is no voltage, check the wiring between the ignition switch and the main relay as well as the #1 (7.5A)(automatic trans.) or #3(7.5A)(manual trans.) fuse.

9. Connect a jumper wire between the BLACK/YELLOW wire, pin 5, and the YELLOW/BLACK wire, pin 7.
10. Turn the ignition switch ON.

a. The fuel pump should work.
b. If the fuel pump does not work, check the wiring between the main relay and the fuel pump, and the wiring from the fuel pump to the ground (BLACK wire).