Control System Functional Test

This test will assure correct functional operation and requires only a few minutes to perform. The test will be made with the car hood down, doors and windows closed, and engine at normal operating temperature and running at 1000 RPM. The A/C must be open with a thermometer installed in the center outlet. Proceed with the tests as follows:

1. Set lever at ICE and temperature dial at 85°.
   1. Hot air must come out both defroster outlets.
   2. Blower must operate at high speed.
2. Set lever at FOG and temperature at 75°
   1. Cooler air must come out defroster outlets.
   2. Blower must operate at lower speed.
3. Set lever at HI and temperature dial at 65°.
   1. Cold air must come out A/C outlets.
   2. Air inlet door in right shroud must be open. (may be slightly noisy).
4. Set lever at AUTO and temperature dial at 85°.
   1. Air must shift from A/C outlets to heater outlet.
   2. At same time blower speed must change.
5. Set lever at LO.
   1. Blower speed must be at low.
6. Set lever at OFF.
   1. All airflow must cease.
7. Set lever at VENT.
   1. Air must come out A/C outlets.
   2. Blower must operate at low speed.
      Fig 1: Adjusting Temperature Dial

      Courtesy of GENERAL MOTORS COMPANY