Too Cold in Vehicle. Pontiac Grand Prix 2001

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2001 🢒 Grand Prix 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Too Cold in Vehicle

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

Value(s)

Yes

Schematic Reference: HVAC Schematics

DEFINITION: The temperature cannot be adjusted, or the heating is insufficient.

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

Important: Both left (driver) and right (passenger) air temperature control concerns are diagnosed in this table.

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

Does the blower motor operate in any speed position?

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

Start the engine.
Place the blower motor switch in the maximum speed position.
Place the mode switch in the MAX position.
Observe the recirculation door.
Place the mode switch in the floor position.

Does the recirculation door move to the outside air position?

Go to Step 5

Go to Vacuum Control System Diagnostic

Are all of the HVAC control module controls except for the blower motor inoperative?

Go to Step 14

Go to Step 6

Inspect the cooling system for the following:

•	A low coolant level

•	A loose or worn accessory drive belt

•	A leaking radiator or heater hoses

•	A kinked radiator or heater hoses

•	A missing radiator cap pressure seal

•	A leaking radiator cap

Did you find and correct the condition?

Go to Step 23

Go to Step 7

Start the engine.
Place the blower switch in the OFF position.
Place the A/C request switch in the OFF position.

Does the A/C compressor operate?

Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 8

Observe the drive shaft of the left and right air temperature actuators.
Place the air temperature switches from the coldest position to the warmest position.

Do the left and the right air temperature actuator drive shafts rotate?

Go to Step 9

Go to Step 10

Inspect the air temperature door and the air temperature actuator for the following conditions:

•	Misaligned air temperature actuator

•	Broken or binding linkages or air temperature door

•	Obstruction that prevents the air temperature door from operating within its full range of motion

•	Missing seals to the air temperature actuator door

•	Misaligned seals to the air temperature actuator door

Did you find and correct the condition?

Go to Step 23

Go to Heating Performance Diagnostic

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

Did you find and correct the condition?

Go to Step 23

Go to Step 11

Test the ground circuit of the suspect air temperature actuator for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 12

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

Did you find and correct the condition?

Go to Step 23

Go to Step 13

Important:: HVAC control module connector must be connected to correctly perform this test.

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

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

0-12 V

Go to Step 18

Go to Step 20

Test the ignition 3 voltage circuit of the HVAC control module for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 15

Test the battery positive voltage circuit of the HVAC control module for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 16

Test the blower motor control OFF circuit of the HVAC control module for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 17

Test the ground circuit of the HVAC control module for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 20

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

Did you find and correct the condition?

Go to Step 23

Go to Step 19

Inspect the suspect air temperature actuator, door and any attaching linkage for binding or a condition that prevents drive shaft rotation.

Did you find and correct the condition?

Go to Step 23

Go to Step 21

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 in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 22

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

Did you complete the replacement?

Go to Step 23

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

Did you complete the replacement?

Go to Step 23

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2