Too Cold in Vehicle. Buick Century 2002

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2002 🢒 Century 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Too Cold in Vehicle

Test Description

The numbers below refer to the step numbers 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 heating is insufficient.

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

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 at the desired speeds?

Go to Step 4

Go to Blower Motor Malfunction

Inspect the cooling system for the following conditions:

•	A low coolant level

•	A loose or worn accessory drive belt

•	A leaking radiator hose or heater hose

•	A kinked radiator hose or heater hose

•	A missing radiator cap pressure seal

•	A leaking radiator cap

Refer to Heating Performance Diagnostic in Heating, Ventilation and Air Conditioning.

Did you find and correct the condition?

Go to Step 20

Go to Step 5

Start the engine.
Place the blower motor switch in the maximum speed position.
Place the mode switch in the MAX position.

Does the recirculation door move to the recirculation position?

Go to Step 6

Go to Air Delivery Improper

Place the mode switch in the VENT or HTR positions

Does the A/C compressor operate?

Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 7

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

Does the left and right air temperature actuator drive shaft rotate at all?

Go to Step 8

Go to Step 9

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

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

•	Broken or binding linkages or air temperature door

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

•	Missing seals to the air temperature door

•	Misaligned seals to the air temperature door

Did you find and correct the condition?

Go to Step 20

Go to Step 9

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 20

Go to Step 10

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 20

Go to Step 11

Test the suspect air temperature door control circuit of the 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 20

Go to Step 12

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

Did you find and correct the condition?

Go to Step 20

Go to Step 13

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

Did you find and correct the condition?

Go to Step 20

Go to Step 14

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 suspect 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 17

Go to Step 15

Inspect for poor connections at the harness connector of the suspect 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 20

Go to Step 16

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 20

Go to Step 18

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 20

Go to Step 19

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 20

Replace the HVAC control module. Refer to Heater and Air Conditioning Control Replacement .

Did you complete the replacement?

Go to Step 20

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2