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Bus +/- Signals Open Or No Response From Memory Heated Seat/Mirror Module

NOTE: After making any repairs, perform BODY 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 BODY, then BODY COMPUTER. If scan tool communicates with Body Control Module (BCM), go to next step. If scan tool does not communicate with BCM, perform BUS +/- SIGNALS OPEN OR NO RESPONSE FROM BODY CONTROL MODULE  test.
  2. Turn ignition off. Disconnect Memory Heated Seat/Mirror Module (MHSMM) connector C4. Using a 12-volt test light connected to ground, probe MHSMM connector C4 terminal No. 2, fused B+ circuit (Red wire). See Figure . If test light illuminates, leave MHSMM connector C4 disconnected and go to step  4 . If test light does not illuminate, leave MHSMM connector C4 disconnected and go to next step.
  3. Substitute a known-good Circuit Breaker No. 2 (CB 2) in junction block. Circuit breakers are identified on inside of left instrument panel end cap. Using 12-volt test light connected to ground, probe MHSMM connector C4 terminal No. 2, fused B+ circuit (Red wire). If test light illuminates, replace faulty circuit breaker No. 2. If test light does not illuminate, repair Red wire for open or short circuit.
  4. Measure resistance between ground and MHSMM connector C4 terminal No. 1, ground circuit (Black wire). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black wire.
    5. NOTE: Steps  5 - 7 are written specifically for use with Chrysler's Diagnostic Readout Box (DRBIII(R)) scan tool.
  5. Turn ignition off. Connect Scope Input Cable (CH7058) to channel one connector on scan tool. Connect Red and Black leads and Cable-To-Probe Adapter (CH7062) to scope input cable. Go to next step.
  6. Using scan tool, select DRB STANDALONE, LAB SCOPE, LIVE DATA, then 12-VOLT SQUARE WAVE. Press F2 for scope. Press F2 again and use down arrow to set voltage range to 20 volts. Press F2 again. Go to next step.
  7. Connect Black lead to chassis ground. Disconnect MHSMM connector C1. Connect Red lead to MHSMM connector C1 terminal No. 26, PCI bus circuit (Violet/Yellow wire). Turn ignition on. Observe voltage display on scan tool lab scope. If voltage pulses from zero to about 7.5 volts, replace MHSMM. See Figure -Figure . See MEMORY HEATED SEAT/MIRROR MODULE  under REMOVAL & INSTALLATION. If voltage does not pulse from zero to about 7.5 volts, go to next step.
  8. Turn ignition off. Disconnect MHSMM connector C1. Disconnect BCM connector C4. Measure resistance of PCI bus circuit (Violet/Yellow wire) between MHSMM connector C1 terminal No. 26 and BCM connector C4 terminal No. 9. See Figure and Figure . 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 Violet/Yellow wire.
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