Checking The Viscous/Cabin Heater Relay - DaimlerChrysler Jeep Grand Cherokee 2002 Service Manual

DRIVEABILITY - DIESEL
Symptom:

*CHECKING THE VISCOUS/CABIN HEATER RELAY

FUSED B+ CIRCUIT OPEN
VISCOUS HEATER RELAY OUTPUT CIRCUIT SHORTED TO VOLTAGE
VISCOUS HEATER RELAY OUTPUT CIRCUIT SHORTED TO GROUND
VISCOUS HEATER RELAY OUTPUT CIRCUIT OPEN
VISCOUS HEATER RELAY
TEST
1 Turn the ignition on.
With the DRB, actuate the Viscous Heater Relay.
Is the clicking during the actuator test?
Yes → Test Complete.
→ Go To 2
No
2 NOTE: If the Viscous Heater Relay fuse or fuselink is open, refer to the
system schematics for all circuits that are powered by the Cabin Heater
Relay fuse or fuselink to determine the cause of the blown fuse/fuselink.
Remove the Viscous Heater Relay.
Using a 12-volt test light connected to ground, probe the Fused B+ circuit in the
Viscous Heater Relay connector.
Does the test light illuminate brightly?
Yes → Go To 3
→ Repair the Fused B+ (Fuse/Fuselink) circuit for an open.
No
3 Turn the ignition off.
Disconnect the Viscous Heater harness connector.
Remove the Viscous Heater Relay.
Turn the ignition on.
Measure the voltage on the Viscous Heater Relay Output circuit.
Is the voltage above 1.0 volt?
Yes → Repair the Viscous Heater Relay Output circuit for a short to
→ Go To 4
No
4 Turn the ignition off.
Disconnect the Viscous Heater harness connector.
Remove the Viscous Heater Relay.
Measure the resistance between ground and the Viscous Heater Relay Output circuit.
Is the resistance above 1000 ohms?
Yes → Go To 5
→ Repair the Viscous Heater Relay Output circuit for a short to
No
POSSIBLE CAUSES
ACTION
Perform ROAD TEST VERIFICATION - VER-2.
voltage.
Perform ROAD TEST VERIFICATION - VER-2.
ground. Inspect the fuse or fuselink and replace as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
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APPLICABILITY
All
All
All
All