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

Relay Terminal Identification:

AUTOMATIC SHUT DOWN (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

J11 30 RD Has battery input voltage supplied through fusible link.

Z1 87 DG/BK Connected to terminal 30 in the energized position, supplies output voltage to the fuel pump, fuel injectors, ignition coil, and 02 sensor heater element.

J2 86 DB Connected to the ignition circuit, provides supply voltage to the relay.

K19 85 DB/YL Connected to the Single Board Engine Controller (SBEC), and grounded by the SBEC, to activate the relay when the ignition switch is in the START or RUN position and a distributor signal is present.

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

AUTOMATIC SHUT DOWN (ASD) RELAY TEST
NOTE: The following test procedures assume that the ignition system is functioning, and that a good spark is evident at the plugs. If this not the case test the ignition system before proceeding with this test.
NOTE: Automatic Shut Down (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. Using a digital voltmeter connect the negative lead to ground and the positive lead to the terminal 30 (red) wire of the ASD relay connector.
^ If battery voltage is present proceed to step 2.
^ If no voltage is present, check fusible links and supply voltage from the battery.
2. Move the voltmeter positive lead to the terminal 87 (DG/BK) wire of the ASD relay connector. Turn the ignition key to the START position and crank the engine.
^ If no voltage is present at terminal 87 (DG/BK) wire proceed to step 3.
^ If battery voltage is present during cranking, the ASD relay is functioning normally and no further testing of the ASD relay is necessary.
3. Move the voltmeter positive lead to the terminal 86 (DB) wire of the ASD relay connector. Turn the ignition key to the RUN position. Battery voltage from the ignition circuit should be present.
^ If voltage is present proceed to step 4.
^ If no voltage is present there is either a bad connection or an open wire between ignition circuit J2 and terminal 86 of the ASD relay. Locate and repair bad connector or open in wire, and test operation.
4. Move voltmeter positive lead to terminal 85 (DB/YL) wire of the ASD relay connector. Turn ignition key to START position, and crank engine, while observing voltage. Voltage should be present and drop to less than 1 volt within 2 seconds during cranking.
^ If voltage does not drop, proceed to step 5.
^ If voltage drops, and there is voltage at terminal 30 (RD wire) and no voltage at terminal 87 (DG/BK) the relay is bad. Replace the ASD relay and check operation.
^ If no voltage is present, disconnect the ASD relay, and connect an ohmmeter between terminal 86 (DB wire) and terminal 85 (DB/YL wire) of the ASD relay and check for continuity. If no continuity exists replace the ASD relay and test operation.
5. Disconnect the 60 way Single Board Engine Controller (SBEC) connector and the ASD relay. Connect an ohmmeter between terminal 85 (DB/YL wire) of the ASD relay connector and the DB/YL wire at pin connector no. 51 of the SBEC 60 way connector. 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.