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Home >> GMC >> 1995 >> Jimmy 4D Utility, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Data Link Communications System >> Trouble Shooting >> VCM Class 2 Data Line
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VCM Class 2 Data Line

  1. Ensure there is proper connection between scan tool and DLC and there are no loose or missing DLC terminals.
  2. If the VCM is not accessible with a scan tool, check for an open in circuit 1807 between DLC terminal No. 2 and the VCM.
  3. Visually inspect for obvious signs of mechanical and electrical damage. Inspect for blown fuses and damaged relays. Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. These circuits may be intermittent or resistive when loaded and should be checked by monitoring the voltage drop with the system under load.
  4. Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary. If no fault is found, go to CLASS 2 DATA LINE DIAGNOSIS  under SYSTEM TESTS.
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