DaimlerChrysler Jeep Grand Cherokee 2002, Service Manual

Page: 231 / 284

Symptom:
*CHECKING THE GLOW PLUG OPERATION
POSSIBLE CAUSES
CHECKING THE GLOW PLUGS
FUSED B+ CIRCUIT OPEN
GLOW PLUG RELAY OUTPUT CIRCUIT SHORTED TO VOLTAGE
GLOW PLUG RELAY OUTPUT CIRCUIT SHORTED TO GROUND
GLOW PLUG RELAY OUTPUT CIRCUIT OPEN
GLOW PLUG RELAY
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Disconnect the Glow Plug harness connectors for all cylinders.
Turn the ignition on.
With the DRBIII
t
, actuate the Glow Plug 1 Relay.
Using a 12-volt test light connected to ground, probe Glow Plug harness connectors
1, 3 and 5 during actuator test.
With the DRBIII
t
, actuate the Glow Plug 2 Relay.
Using a 12-volt test light connected to ground, probe Glow Plug harness connectors
2 and 4 during actuator test.
Does the test light cycle on and off at each Glow Plug harness connector during
actuation?
All
Yes
→
Go To 2
No
→
Go To 3
2 Refer to the Service Information and perform the Glow Plug Test.
Are all Glow Plugs operating properly? All
Yes
→
Test Complete.
No
→
Replace the Glow Plug(s) as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
3 NOTE: If the Glow Plug Relay fuse or fuselink is open, refer to the system
schematics for all circuits that are powered by the Glow Plug Relay fuse or
fuselink to determine the cause of the blown fuse/fuselink.
Remove the Glow Plug Relay of the affected cylinder(s).
Using a 12-volt test light connected to ground, probe the Fused B+ circuit in the Glow
Plug Relay connector.
Does the test light illuminate brightly? All
Yes
→
Go To 4
No
→
Repair the Fused B+ (Fuse/Fuselink) circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
223
DRIVEABILITY - DIESEL
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