Main Relay (Computer/Fuel System): Testing and Inspection

Main Relay Schematic:

Fig. 54 Main Relay Test Points:

1. Remove the main relay, near the under-dash fuse box.
2. Attach the positive battery terminal to the #4 terminal, and the negative battery terminal to the #8 terminal of the main relay. Then check for continuity between the #5 and #7 terminals of the main relay.

a. If there is continuity, go to step 3.
b. If there is no continuity, replace the main relay and retest.

3. Attach the positive battery terminal to the #5 terminal, and the negative battery terminal to the #2 terminal of the main relay. Then check for continuity between the #1 and #3 terminals of the main relay.

a. If there is continuity, go to step 4.
b. If there is no continuity, replace the main relay and retest.

4. Attach the positive battery terminal to the #3 terminal, and the negative battery terminal to the #8 terminal of the main relay. Then check for continuity between the #5 and #7 terminals of the main relay.

a. If there is continuity, the relay is OK.
b. If the fuel pump still does not work, see HARNESS TEST.
c. If there is no continuity, replace the relay and retest.