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

Relay Terminal Identification:

ASD RELAY TERMINAL IDENTIFICATION
The following is a list of the terminal numbers, with circuit codes, and color codes, and their function:

Circuit No. Terminal No. Color Code Description

A14 30 RD/WT Has battery input voltage supplied through fusible link.

A61 87 DG/BK Connected to A14 circuit (terminal 30) in the energized position, supplies output voltage to fuel pump, O2 sensor, fuel injectors, and coil.

A21 86 DB Connected to the electromagnet, (diode) and the Single Board Engine Controller (SBEC). The SBEC provides input voltage to relay.

K51 85 DB/YL Connected to the electromagnet (diode) and grounded by the SBEC when distributor signal is present.

N/A 87A N/A Not used in these applications.

ASD RELAY TEST

NOTE: The ASD relay operation may be tested with the use of the DRB II scanner or equivalent.
If no scanner is available proceed with the following test.

1. Connect a voltmeter to the A14 (terminal 30) wire at the ASD connector. Check for battery voltage. If no voltage is present, check fusible links and supply voltage from the battery. If voltage is present proceed to step 2.
2. Connect the voltmeter to the A61 (terminal 87) wire at the ASD connector. Turn the ignition key to the START position and crank the engine. If output voltage is present during cranking, the ASD relay is functioning normally and no further testing of the ASD relay is necessary. If no voltage is present at the A61 wire, proceed to step 3.
3. Connect the voltmeter to the K51 (terminal 85) wire at the ASD connector. Turn the ignition key to the RUN position. Input voltage from the SBEC to the ASD relay should be present. If voltage is present proceed to step 4. If no voltage is present, disconnect the 60-Way SBEC connector, and the ASD relay connector. Connect an ohmmeter between the K51 (terminal 85) wire and the DB/YL wire at pin connector no. 51 of the SBEC connector, and check for continuity. If continuity exists, the problem is computer related. Testing and Inspection
If no continuity exists, repair open in wire, reconnect SBEC and ASD relay, and test operation.
4. Connect voltmeter to A21 (terminal 86) wire at ASD connector. Turn ignition key to START position, and crank engine, while observing voltage at A21. Voltage should be present at A21 and drop to less than 1 volt within 2 seconds during cranking. If voltage drops ASD relay is functioning, and no further testing of the ASD relay is necessary. If voltage does not drop, proceed to step 5. If no voltage is present, disconnect the ASD relay, and connect an ohmmeter between the A21 (terminal 86) and K51 (terminal 85) of the ASD relay and check for continuity. If no continuity exists replace and ASD relay and test operation.
5. Disconnect the 60-Way SBEC connector and ASD relay. Connect an ohmmeter between the A21 wire at the ASD relay connector and the DB wire at pin connector no. 9 of the SBEC. Check for continuity. If no continuity exists repair open in wire, reconnect SBEC and ASD relay, and test operation. If continuity exists, the problem is computer related. Testing and Inspection