Diagnostic Procedure

WARNING: This page is about a different car, the 2005 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.

DIAGNOSTIC PROCEDURE - REAR WINDOW DEFOGGER INOPERATIVE

TEST	ACTION	APPLICABILITY
1	With the DRBIII®, read the Body Control Module DTC's. Are there any Rear Defogger Relay DTC's present? Yes --> Refer to the REAR DEFOGGER RELAY DTC'S . Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 2	All
2	Toggle the Rear Defogger switch and observe the indicator. Does the indicator toggle on and off when the switch is pressed? Yes --> Go To 3 No --> Go To 4	All
3	Turn the ignition on. Turn the Rear Window Defogger on. Measure the voltage between the Rear Window Defogger Relay Output circuit at the defogger grid on the rear window to ground. Is the voltage above 12.0 volts? Yes --> Repair the open in the Rear Window Defogger Grid or the Grid Ground circuit. Perform BODY VERIFICATION TEST - VER 1 . No --> Repair the Rear Window Defogger Relay Output circuit for an open. Perform BODY VERIFICATION TEST - VER 1 .	All
4	With the DRBIII® in Inputs/Outputs, read the R Defogger SW state. Cycle the Rear Defogger On/Off button and observe the DRBIII. Did the DRBIII® display change from Open to Closed? Yes --> Go To 5 No --> Go To 10	All
5	Check the Power Distribution Center fuse 19. Is the fuse open. Yes --> Check for a short to ground and replace the PDC fuse. Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 6	All
6	Check Junction Block fuse 29. Is the fuse open. Yes --> Check for a short to ground and replace the Junction Block fuse. Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 7	All
7	Remove the Rear Window Defogger Relay from the Junction Block. Measure the voltage of the Fused B(+) circuit in the Rear Window Defogger Relay connector. Is the voltage above 10.0 volts? Yes --> Go To 8 No --> Repair the open Fused B(+) circuit from PDC fuse #19. Perform BODY VERIFICATION TEST - VER 1 .	All
8	Remove the Rear Window Defogger Relay from the Junction Block. Install a known good relay in the Rear Window Defogger Relay connector. Turn the ignition on. Toggle the Rear Window Defogger switch and observe the indicator. Does the Rear Window Defogger indicator illuminate? Yes --> Replace the original Rear Window Defogger Relay. Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 9	All
9	Gain access to the A/C Heater Control C2 connector. Toggle the Rear Window Defogger switch in the next step. While back probing, measure the voltage of the Fused Rear Window Defogger Relay Output circuit. Is there any voltage present? Yes --> Replace the A/C-Heater Control. Perform BODY VERIFICATION TEST - VER 1 . No --> Repair the Fused Rear Window Defogger Relay Output circuit for an open. Perform BODY VERIFICATION TEST - VER 1 .	All
10	Turn the ignition off. Disconnect the A/C-Heater Control C2 connector. Turn of all interior lights. Measure the resistance of the Ground circuit in the C2 connector. Is the resistance below 5.0 ohms? Yes --> Go To 11 No --> Repair the ground circuit for an open. Perform BODY VERIFICATION TEST - VER 1 .	All
11	Turn the ignition off. Disconnect the A/C-Heater Control C2 connector. With the DRBIII® in Inputs/Outputs, read the R Defogger SW state. Connect a jumper wire between Rear Window Defogger Control and ground. Did the DRBIII® display change from Open to Closed? Yes --> Replace the A/C-Heater Control. Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 12	All
12	Turn the ignition off. Disconnect the A/C-Heater Control C2 connector. Disconnect the Body Control Module C1 connector. Measure the resistance of the Rear Window Defogger Control circuit between the A/C- Heater Control C2 connector and the Body Control Module C1 connector. Is the resistance below 5.0 ohms? Yes --> Replace and program the Body Control Module in accordance with the Service Information. Perform BODY VERIFICATION TEST - VER 1 . No --> Repair the Rear Window Defogger Control circuit for an open. Perform BODY VERIFICATION TEST - VER 1 .	All