GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Monte Carlo 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 Functional Check
  1. The following conditions indicate that the electrical circuits are functioning correctly:
    2. • The air conditioning blower motor operates at the appropriate speed with the control (mode) in any position except OFF. Verify that the compressor clutch also engages.
    • The blower motor will not operate in any speed with the control in the OFF position.
  2. The heater A/C control assembly (mode selector) is operating correctly when the designated outlets distribute air.

Perform the following A/C Function Tests.

Preliminary Checks:

    • Inspect for temperature change when the temperature knob position is changed.
        On dual control systems Inspect the left side and right side outlets when the temperature control position is changed.
    • Listen for a decrease in air noise, due to the closing of the recirculation valve, when going from MAX mode to A/C mode.
    • Inspect all of the I/P outlets. Verify that the following conditions exist:
       - The barrel rotates
       - The vane operates
       - The barrel and vanes hold the present position in HI blower operation.

HVAC System Check

Step

Action

Value(s)

Yes

No

1
  1. Place the ignition switch in the ON position.
  2. Observe the heater-A/C control display.

Is the heater-A/C control display on?

--

Go to Step 2

Go to Step 7

2
  1. Place the heater-A/C control in the DEFROST mode .
  2. While listening to the blower motor, change the blower speed using the fan speed control from LOW to High on the heater-A/C control.

Does the blower motor turn on and change speed?

--

Go to Step 3

Go to HVAC Blower Controls System Check

3
  1. Place the heater-A/C control in the A/C mode.
  2. Place the temperature control in the LOW setting.

Does the A/C compressor turn on and off properly when using the A/C system?

--

Go to Step 4

Go to Powertrain Control Module Controlled Air Conditioning Description in 3.1L Engine Controls or Go to Powertrain Control Module Controlled Air Conditioning Description in 3.8L Engine Controls

4

Test each of the air flow modes by selecting the individual modes with the MODE control on the heater-A/C control.

Does the air flow move through the proper vents for each mode?

--

Go to Step 5

Go to HVAC Air Delivery System Check

5

Turn the driver temperature control from full cold to full hot.

Does the driver air temperature control operate properly and is the air temperature display accurate?

Go to Step 6

Go to Driver Temperature Control Inoperative

6

On vehicles equipped with dual temperature controls :

  1. Set the driver temperature to 25°C (76°F).
  2. Turn the passenger temperature control from full cold to full hot.

Does the passenger air temperature control operate properly?

--

System OK

Go to Driver and Passenger Temperature Control Inoperative

7

Observe the radio display.

Is the radio display also inoperative?

--

Go To Interior Lights Dimming System Check in Lighting Systems

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