Low engine idle can be caused by high A/C compressor loads due to high head pressures resulting from compressor operation without engine cooling fan operation while in defrost mode.
This condition can be corrected by installing an additional engine cooling fan relay, P/N 14078902 (see diagram) to operate the engine cooling fan in defrost mode. A connector body, P/N 12010015, and terminal ends, P/N 8905087, are available for simplification of the installation of the additional cooling fan relay mentioned in the above article.
The relay should be installed on the cowl, adjacent to the pressure cycling switch. Any wiring run through the cowl should be routed through existing grommets and care be taken to maintain cowl sealing.
Labour Operation Number T1094
Labour Time .4 hours
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.