For 1990-2009 cars

# IMPROPER TEMPERATURE CONTROL IN DRIVER SELECTED MODES

#### VEHICLES AFFECTED: 1986-88 E

Some 1986-1988 Toronados may exhibit a condition where the discharge air temperature does not control properly when the forced upper mode or forced lower mode settings on the control panel are selected. Should this condition occur the symptoms are:

Discharge air from the A/C outlets becomes too warm when the forced upper mode is selected.

Discharge air from the heater outlet becomes too cold when the forced lower mode is selected.

This condition may be due to the calibration value for the forced upper and lower modes within the BCM PROM. To repair this condition enter diagnostics as outlined in Section 8D of the Service Information Manual to check the BCM PROM I.D. and replace, if necessary, with the new part number from the table below:

Old New PROM PROM Model I.D. New P/N I.D. ----- ---- -------- ----- 1986 Toronado 6763 16124160 4163 1987 Toronado 5453 16124161 4173 1988 Toronado 173 16121073 1053 (before VIN 309680)

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.