Too Hot in Vehicle. Buick Rendezvous

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2007 🢒 Rendezvous - FWD 🢒 HVAC 🢒 Heating, Ventilation, and Air Conditioning 🢒 Too Hot in Vehicle

Diagnostic Aids

The Mitsubishi scroll type A/C compressor carries an internal thermal cut off switch. The thermal cut off switch normal operation is to open and disable the compressor under extreme load and temperatures above 155°C (311°F). The internal thermal cut off switch is non-serviceable.

Test Description

The number below refers to the step number on the diagnostic table.

The voltage will vary between 0-12 volts during normal operation. The HVAC control module connector must be connected during this step.

Step

Action

Values

Yes

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The temperature cannot be adjusted, or the cooling is insufficient during A/C operation.

Important: The single C60 HVAC Manual air temperature actuator or the dual CJ3 HVAC Manual air temperature actuator equipped system is diagnosed in this table.

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

Turn ON the ignition, with the engine OFF.
Place the blower motor switch in each speed position.

Does the blower motor operate in any of the speed positions?

Go to Step 3

Go to Blower Motor Inoperative

Does the blower motor operate in each speed position?

Go to Step 4

Go to Blower Motor Malfunction

Does the Too Hot in Vehicle concern occur when A/C cooling is desired?

Go to Step 5

Go to Step 7

IMPORTANT:: For A/C compressor operation, the ambient air temperature must be above 3°C (38°F).

Start the engine.
Place the blower motor switch in the maximum speed position.
Place the mode switch in the VENT position.
Place the A/C request switch in the ON position.
Place both temperature switches or the single temperature switch in the coldest position.

Does the A/C compressor operate?

Go to Step 6

Go to HVAC Compressor Clutch Does Not Engage

Perform the refrigerant system performance test. Refer to Air Conditioning (A/C) System Performance Test .

Did you find and correct the condition?

Go to Step 18

Go to Step 7

Observe the drive shaft to the air temperature actuator or actuators.
Place the air temperature switch or switches from the coldest to the warmest position.

Does the drive shaft of the air temperature actuator or actuators rotate?

Go to Step 8

Go to Step 9

Inspect the air temperature door of the air temperature actuator or actuators for the following conditions:

•	A misaligned air temperature actuator--Refer to Temperature Valve Actuator Replacement or Temperature Valve Actuator Replacement - Right Side or Temperature Valve Actuator Replacement - Left Side .

•	Broken or binding linkages or air temperature door

•	An obstruction that prevents the air temperature door or doors from operating within the full range of motion

•	Missing seals to the air temperature door or doors

•	Misaligned seals to the air temperature door or doors

Did you find and correct the condition?

Go to Step 18

Go to Testing for Intermittent Conditions and Poor Connections

Test the ignition 3 voltage circuit of the air temperature actuator or actuators for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 18

Go to Step 10

Test the ground circuit of the air temperature actuator or actuators for an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 18

Go to Step 11

Test the door control circuit of the air temperature actuator or actuators for an open, a high resistance, a short to ground, or a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 18

Go to Step 12

Important: Ensure that the HVAC control module connector is connected during this step in order to avoid misdiagnosis.

Turn ON the ignition, with the engine OFF.
Measure the voltage from the door control circuit of the air temperature actuator or actuators to a good ground.
Place the air temperature switch or switches from the coldest position to the warmest position.

Is the voltage within the specified values with a smooth transition between cold and hot?

0 V at cold

12 V at hot

Go to Step 13

Go to Step 15

Inspect for poor connections at the harness connector of the air temperature actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 18

Go to Step 14

Inspect the air temperature door or doors and the air temperature actuator or actuators for the following conditions:

•	Replace the air temperature actuator. Refer to Temperature Valve Actuator Replacement or Temperature Valve Actuator Replacement - Right Side or Temperature Valve Actuator Replacement - Left Side .

•	Broken or binding linkages or air temperature door or doors.

•	An obstruction that prevents the air temperature door or doors from operating within the full range of motion

•	Missing seals to the air temperature door or doors

•	Misaligned seals to the air temperature door or doors

Did you find and correct the condition?

Go to Step 18

Go to Step 16

Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 18

Go to Step 17

Replace the air temperature actuator. Refer to Temperature Valve Actuator Replacement or Temperature Valve Actuator Replacement - Right Side or Temperature Valve Actuator Replacement - Left Side .

Did you complete the replacement?

Go to Step 18

Replace the HVAC control module. Refer to Control Module References .

Did you complete the replacement?

Go to Step 18

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2