1985 6000
The speedometer on some 1985 6000 vehicles may go to zero intermittently, especially when going over bumps or with engine "rocking" during acceleration.
This condition may be caused by the wiring harness to the VSS (PM generator on the transaxle) being routed too close to the engine generator leads or damaged wiring to the VSS.
To repair this condition, remove the connector from the VSS (put vehicle on a lift to do this). Inspect the harness connector terminals for damage and repair if necessary. Inspect the VSS wiring insulation for damage, repair where required. Reroute the connector and harness to relieve any tension.
If the harness is too tight, open the conduit, cut the tape, in order to reposition the wires closer to the front of dash (away from the engine) as shown.
The condition has been corrected in production, after VIN 2G2AF19R1F1216371.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.