For 1990-2009 cars

# SERVICE MANUAL UPDATE-SEC.8A ELEC. DIAGNOSTIC/CELSIUS-FAHR.

#### SUBJECT: SERVICE MANUAL UPDATE/SECTION 8A/ELECTRICAL DIAGNOSTIC (OPERATION OF CELSIUS/FAHRENHEIT)

#### VEHICLES AFFECTED: 1985-87 OLDS C/H MODELS

The Heater and A/C Control Assembly on vehicles equipped with Tempmatic Air Conditioning (C65) can be programmed to display the external and set temperature in degrees Celsius instead of degrees Fahrenheit when the Ignition Switch is turned to RUN. Vehicles being operated primarily in the United States should be programmed to display degrees Celsius.

To have the temperature displayed in degrees Celsius upon power-up, a wire connects Heater and A/C Control Assembly terminals C and H. This wire should not be present in vehicles operated primarily in the United States.

If a vehicle is received that displayed temperature in degrees Celsius when the Ignition Switch is turned to RUN, the Heater and A/C Control Assembly can be reprogrammed to display degrees Fahrenheit by removing or cutting the wire that connects terminals C and H. Be sure to tape the cut ends to prevent shorts. This wire can then be pulled out of the harness.

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.