GM Service Manual Online
For 1990-2009 cars only

A/C COMPRESSOR RUNS WHEN BLOWER SWITCH IN LOW

VEHICLES AFFECTED: 1985 'M' Van with Air Conditioning

Some 1985 'M' Vans may experience the air conditioning compressor being turned on when the blower switch is in the low position. This condition may be the result of a diode being installed backwards in the blower motor resistor. The correct position of the diode is shown below in Figure No. 1.


Object Number: 87993  Size: MF

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.