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Home >> Chrysler >> 2003 >> Intrepid ES, 3.5 V >> Repair and Diagnosis >> External Pages >> Different car >> Section 4 (Automatic Transmission Diagnosis) >> Symptom Tests >> Back-Up Lights Inoperative >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Dodge Intrepid, 2002 Chrysler Intrepid, 2002 Chrysler Concorde, and 2002 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition on and apply brakes. Place gearshift lever in "R" position. If one or both back-up lights illuminate, go to next step. If neither back-up light illuminates, go to step  3.
  2. If only one back-up light illuminates, fault is in bulb or circuit to inoperative bulb. Check bulb and socket for corrosion. Using wiring diagram as a guide, inspect wiring and connectors associated with circuits in question. See WIRING DIAGRAMS . Repair as necessary. If both back-up lights illuminate, conditions necessary to create this malfunction are not present at this time. Wiggle wires while checking for shorted and open circuits. If circuits are okay and back-up lights operate, Transmission Range (TR) sensor is most likely cause of malfunction. Repair as necessary.
  3. Remove back-up light bulbs. Measure resistance of bulbs. If resistance is greater than 5 ohms, replace faulty bulb(s), and retest system. If bulbs test okay, reinstall bulbs and go to next step.
    4. NOTE: Failure to remove starter relay can cause a NO RESPONSE FROM TCM condition.
  4. Turn ignition off. Remove starter relay from power distribution center. See Figure. This prevents vehicle from starting in gear. Install Transmission Simulator (8333). Turn ignition on. Press REVERSE LIGHT TEST button on simulator. If either back-up light illuminates while button is pressed, go to next step. If neither back-up light illuminates while button is pressed, go to step  6.
  5. Replace TR sensor. See REMOVAL & INSTALLATION in appropriate SERVICING article in AUTOMATIC TRANSMISSIONS.
  6. Connect test light clamp end to 12-volt source. Probe ground circuit in bulb socket with test light. If test light does not illuminate, repair back-up light ground circuit to bulb socket and check operation of back-up lights in "R" position. If test light illuminates, go to next step.
  7. Turn ignition switch to LOCK position. Disconnect TR sensor harness connector. Turn ignition on. Using test light connected to ground, probe fused ignition switch output (RUN) circuit at TR sensor harness connector terminal No. 1. See WIRING DIAGRAMS . If test light illuminates, go to next step. If test light does not illuminate, repair open circuit. If fuse is open, ensure to check for a short to ground. Check operation of back-up lights in "R" position.
  8. Turn ignition switch to LOCK position. Measure resistance of back-up light feed circuit between bulb socket and TR sensor harness connector terminal No. 6. See WIRING DIAGRAMS . If resistance is greater than 5 ohms, repair open back-up light feed circuit. Check operation of back-up lights in "R" position. If resistance is 5 ohms or less, go to next step.
  9. Measure resistance between ground and back-up light feed circuit at TR sensor harness connector terminal No. 6. If resistance is less than 5 ohms, repair short to ground in back-up light supply circuit. Check fuse and replace as necessary. If resistance is 5 ohms or greater, test is complete.
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