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Home >> Cadillac >> 1996 >> Fleetwood Base >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Central Control Module >> Diagnosing & Repairing CCM DTCS >> DTC 25, Courtesy Output Circuit (CKT Open Or Shorted To GRND) >> Testing
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DTC 25, Courtesy Output Circuit (CKT Open Or Shorted To GRND): Testing

  1. Check for DTC 23. Diagnose and repair DTC 23 if present. Open door. Turn ignition switch to RUN position. Close all doors. Observe courtesy lights. If courtesy lights do not illuminate, go to step 3). If courtesy lights illuminate, check for short to ground in courtesy lights output circuit. If circuit is okay, go to next step.
  2. Turn ignition switch to OFF position. Check for poor connections at CCM connector. If connections are okay, reconnect CCM connector and all other components. Clear DTCs and check if DTC resets. If DTC resets, replace CCM. If DTC does not reset, problem may be intermittent. Try to recreate fault while performing test by wiggling wiring and connectors. Check for poor connections at all connectors that may be causing intermittent condition.
  3. Check DIL fuse No. 27 located in instrument panel fuse block. If fuse is okay, go to next step. If fuse is blown, turn ignition switch to OFF position. Repair short to ground in DIL supply circuit between relay and DIL-controlled components, or in DIL fuse No. 27 circuit between fuse and relay. Replace fuse.
  4. Close all doors. Using DVOM, backprobe CCM connector C2 terminal C12 to ground and measure voltage. If voltage is less than one volt, go to step 6). If voltage is greater than one volt, go to next step.
  5. Turn ignition switch to OFF position. Check for poor connections at CCM connector. If connections are okay, reconnect CCM connector and all other components. Clear DTCs and check if DTC resets. If DTC resets, replace CCM. If DTC does not reset, problem may be intermittent. Try to recreate fault while performing test by wiggling wiring and connectors. Check for poor connections at all connectors that may be causing intermittent condition.
  6. Using DVOM, backprobe DIL relay connector terminal B6 to ground and measure voltage. If voltage is less than one volt, repair short to ground in DIL fuse No. 27 circuit between fuse and relay. If voltage is greater than one volt, using DVOM, measure voltage at DIL relay connector terminal C4. If voltage is less than one volt, check for poor connections at DIL relay connector. If connections are okay, replace relay. If voltage is greater than one volt, repair open in courtesy lights output circuit between CCM and splice, or in DIL supply circuit between relay and splice.
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