LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Chrysler >> 2002 >> Intrepid Base >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Body Control Modules >> System Tests >> Electrically Heated Systems >> Rear Window Defogger Inoperative With ATC
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Rear Window Defogger Inoperative With ATC

NOTE: After making any repairs, perform MEMORY HEATED SYSTEM VERIFICATION TEST  under VERIFICATION TESTS.

Possible Causes:

Testing

  1. Turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, select INPUTS/OUTPUTS, then read EBL SW status. Press defogger switch on, then off. If scan tool displays EBL SW: OPEN, then EBL SW: CLOSED, go to next step. If scan tool does not display EBL SW: OPEN, then EBL SW: CLOSED, replace Automatic Temperature Control (ATC) module. See REMOVAL & INSTALLATION in AUTOMATIC A/C-HEATER SYSTEMS article in HVAC.
  2. Turn ignition off. Measure resistance between ground and left bus bar on rear window. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in rear window defogger grid ground circuit. SeeREAR WINDOW DEFOGGERS & HEATED MIRRORS - CONCORDE, INTREPID & 300M article.
  3. Turn ignition on. Turn defogger on. Using a 12-volt test light connected to ground, probe right bus bar on rear window. If test light does not illuminate, go to next step. If test light illuminates, repair open in rear window defogger grid. SeeREAR WINDOW DEFOGGERS & HEATED MIRRORS - CONCORDE, INTREPID & 300M article.
  4. Turn ignition off. Remove rear window defogger relay. Turn ignition on. Measure voltage between ground and rear window defogger relay connector terminals No. 4 and 8, fused B+ circuits (Black/Pink wires). See Figure . If voltage is more than 10 volts on both terminals, leave rear window defogger relay removed and go to next step. If voltage is not more than 10 volts on both terminals, go to step  8 .
    5. CAUTION: DO NOT leave jumper wire connected for a long period of time.
  5. Connect a fused jumper wire between rear window defogger relay connector terminals No. 2, rear window defogger relay output circuit (Black/White wire) and No. 4, fused B+ circuit (Black/Pink wire). Measure voltage between ground and right bus bar on rear window. If voltage is more than 10 volts, remove jumper wire, leave rear window defogger relay removed and go to next step. If voltage is 10 volts or less, remove jumper wire and repair open in Black/White wire.
  6. Turn ignition off. Connect a 12-volt test light between rear window defogger relay connector terminals No. 4, fused B+ circuit (Black/Pink wire) and No. 6, rear window defogger relay control circuit (Dark Blue/White wire). Turn ignition on. Turn rear window defogger on. If test light does not illuminate, leave rear window defogger relay removed and go to next step. If test light illuminates, replace rear window defogger relay. SeeREAR WINDOW DEFOGGERS & HEATED MIRRORS - CONCORDE, INTREPID & 300M article.
  7. Turn ignition off. Disconnect Body Control Module (BCM) connector C4. Check, clean and repair BCM connectors as necessary. Connect a fused jumper wire between ground and BCM connector C4 terminal No. 14, rear window defogger relay control circuit (Dark Blue/White wire). See Figure . Measure resistance between ground and rear window defogger relay connector terminal No. 6, rear window defogger relay control circuit (Dark Blue/White wire). If resistance is less than 5 ohms, replace BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. If resistance is 5 ohms or more, repair open in Dark Blue/White wire.
  8. Turn ignition off. Remove and inspect Electric Back Light (EBL) fuse "A" in Power Distribution Center (PDC). See Figure . If fuse is open, go to next step. If fuse is okay, repair open in fused B+ circuit (Black/Pink wire) between PDC and rear window defogger relay connector.
  9. Remove rear window defogger relay. Measure resistance between ground and rear window defogger relay connector terminals No. 4 and 8, fused B+ circuits (Black/Pink wires). See Figure . If resistance is less than 100 ohms on either terminal, repair short to ground in Black/Pink wire(s). If resistance is 100 ohms or more on both terminals, go to next step.
  10. Replace fuse "A". Install rear window defogger relay. Turn ignition on. Turn rear window defogger on. If rear window defogger operates and blows fuse, repair short to ground in rear window defogger relay output circuit (Black/White wire) between rear window defogger relay connector and rear window defogger grid. If rear window defogger operates without blowing fuse, system is currently operating properly. Fault may be intermittent. Check related wiring and connectors for poor connections or damage to wiring harness. See WIRING DIAGRAMS  . Repair any problems found as necessary. If no problems are found, check if any Technical Service Bulletins (TSBs) apply to vehicle. If no TSBs apply, test is complete.
scientia non olet · About LEMON Manuals