B350 1 Ton Van V8-5.9L VIN Z (1992)
Main Relay (Computer/Fuel System): Testing and Inspection
OPERATION
The following operations/tests apply to these relays only: Automatic Shutdown (ASD) and Fuel Pump. For operations/tests on all other relays,
refer to the appropriate section of this service manual.
Relay Terminals
RELAY TERMINAL NUMBERS
The relay terminal numbers from can be found on the bottom of the relay:
^
Terminal number 30 is connected to battery voltage and can be switched or B + (hot) at all times.
^
Terminal number 87A is connected (a circuit is formed) to terminal 30 in the de-energized (normally OFF) position.
^
Terminal number 87 is connected (a circuit is formed) to terminal 30 in the energized (ON) position. Terminal number 87 then supplies
battery voltage to the component being operated.
^
Terminal number 86 is connected to a switched (+)power source.
^
Terminal number 85 is grounded by the PCM.
TESTING
1. Remove relay before testing.
2. Using an ohmmeter, perform a resistance test between terminals 85 and 86. Resistance value (ohms) should be 75 ± 5 ohms for resistor equipped
relays.
3. Connect the ohmmeter between terminals number 87A and 30. Continuity should be present at this time.
4. Connect the ohmmeter between terminals number 87 and 30. Continuity should not be present at this time.
5. Use a set of jumper wires (16 gauge or smaller). Connect one jumper wire between terminal number 85 (on the relay) to the ground side (-) of a 12
Volt power source.
