For 1990-2009 cars

# A/C CONTROL PANEL IN CELCIUS ERRATIC TEMPERATURE CONTROL

#### VEHICLES AFFECTED: 1986 Buick 'C' and 'H' Models Equipped With Option C-68

Effective with Start of Production until approximately January 13, 1986, all Buick 'C' and 'H' models equipped with C68 air conditioning, will have the temperature readout in English units as opposed to Metric units. This change was necessitated due to the omission of an Electromagnetic Interference (E.M.I.) hardening process in the Metric circuitry of the control unit.

There were, however a small number of early build 'C' models which contained control heads displaying temperature in Metric units. These units could develop an erratic temperature control condition in cold weather.

The only correction for this condition is to remove the ground wire (black with orange tracer) located in cavity 11 of the control head connector. This will result in an English unit readout on the control head.

#### NOTE: A new control head will not correct the condition on the early build vehicles.

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.