For 1990-2009 cars

# INSUFFICIENT HEAT DISTRIBUTION ADJUST HEATER-A/C PROGRAMMER

HEATER AND A/C PROGRAMMER ADJUSTMENT TO ASSIST HEATER OPERATION (REVISED TO UPDATE INFORMATION)

#### VEHICLES AFFECTED: 1985-1988 DELTA 88 AND 98 MODELS WITH ----------------- ELECTRONIC COMFORT CONTROL (C65)

A comment of insufficient heat distribution may be received on some 1985-88 Delta 88 and Ninety-Eight models equipped with Electronic Comfort Control (C65). Check all root causes for the condition such as in-car and outside temperature sensors, remove air inlet valve vacuum restrictor from vacuum harness and change heater outlet to new part number 25533710 released by GM PARTS in January 1988.

If the above procedures do not repair the condition, change the programmer. DO NOT adjust the potentiometer.

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.