Grand Cherokee 4WD V8-4.7L VIN N (2000)
Auto Shut Down (ASD) Relay: Testing and Inspection
Fig. 17 Relay Terminals
Fig. 18 Relay Terminals
To perform a complete test of the fuel pump, ASD or oxygen sensor heater relay, or its circuitry, refer to the DRB scan tool and the appropriate
Powertrain Diagnostic. To test the relay only, refer to the following: The terminals on bottom of each relay are numbered or.
OPERATION
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Terminal number 30 is connected to battery voltage. For both the ASD and fuel pump relays, terminal 30 is connected to battery voltage at all
times.
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The PCM grounds coil side of relay through terminal number 85.
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Terminal number 86 supplies voltage to Coil side of relay.
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When the PCM de-energizes the relay, terminal number 87A connects to terminal 30. This is the OFF position. In the OFF position, voltage is not
supplied to rest of circuit. Terminal 87A is the center terminal on relay.
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When the PCM energizes the ASD and fuel pump relays, terminal 87 connects to terminal 30. This is the ON position. Terminal 87 supplies
voltage to rest of circuit.
TESTING
The following procedure applies only to ASD, oxygen sensor heater and fuel pump relays.
1. Remove relay from PDC connector before testing.
2. With relay removed from vehicle, use an ohmmeter to check resistance between terminals 85 and 86. The resistance should be between 75 ± 5
ohms.
3. Connect ohmmeter between terminals 30 and 87A. Ohmmeter should show continuity between terminals 30 and 87A.
4. Connect ohmmeter between terminals 87 and 30. Ohmmeter should not show continuity at this time.
