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Left Seat Heat Output Open

NOTE: Perform MEMORY SYSTEM TEST 1A  before proceeding with this test. For connector terminal identification and wiring diagrams, see BODY CONTROL COMPUTER - INTRODUCTION. Perform VERIFICATION TEST: VER-4A  after each repair.
CAUTION: Always turn ignition switch to OFF position prior to disconnecting or connecting any module connector.
  1. Turn ignition off. Disconnect Memory Heated Seat/Mirror Module (MHSMM) 12-pin harness connector. MHSMM is located under front of seat. See Figure. Using ohmmeter, measure resistance between ground and terminal No. 12 (Red/Dark Green wire) on 12-pin harness connector. If resistance is less than 8.5 ohms, replace MHSMM. If resistance is 8.5 ohms or greater, go to next step.
  2. Disconnect left seat cushion heater 4-pin connector. Measure resistance of Red/Dark Green wire between terminal No. 12 on MHSMM 12-pin harness connector and terminal "A" on left seat cushion heater 4-pin harness connector. If resistance is 5 ohms or greater, repair open Red/Dark Green wire. If resistance is less than 5 ohms, go to next step.
  3. Measure resistance between terminals "A" (Red/Dark Green wire) and "B" (Brown/Black wire) on left seat cushion heater component connector. If resistance is 2.5 ohms or greater, replace seat cushion. If resistance is less than 2.5 ohms, go to next step.
  4. Disconnect seat back heater 2-pin connector. Measure resistance of Brown/Black wire between terminal "B" on seat cushion heater 4-pin component connector and terminal "A" on seat back heater 2-pin harness connector. If resistance is 5 ohms or greater, repair open Brown/Black wire. If resistance is less than 5 ohms, go to next step.
  5. Measure resistance between seat back heater 2-pin component connector. If resistance is 2.5 ohms or greater, replace seat back. If resistance is 2.5 ohms or less, repair open Black wire (ground circuit).