Too Cold in Vehicle. HUMMER H3 2007

GM Service Manual Online

For 1990-2009 cars only

Makes 🢒 HUMMER 🢒 2007 🢒 H3 🢒 HVAC 🢒 HVAC - Manual 🢒 Too Cold in Vehicle

Test Description

The numbers below refer to the step numbers on the diagnostic table.

The HVAC control module is inoperative when the module does not respond to an operator control request.

If no condition is found with all conditions listed, then compare door travel to a known good vehicle.

Step

Action

Values

Yes

Schematic Reference: HVAC Schematics

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

Did you review the HVAC operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

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

Does the blower operate in any of the speed positions?

Go to Step 3

Go to Blower Motor Malfunction

Does the blower actuator operate correctly for each speed position?

Go to Step 4

Go to Blower Motor Malfunction

Is the HVAC control assembly inoperative?

Go to Step 17

Go to Step 5

Inspect the cooling system for the following:

•	A low coolant level

•	A loose or worn accessory drive belt

•	Leaking radiator hoses or leaking heater hoses

•	Kinked radiator hoses or kinked heater hoses

•	A missing radiator cap pressure seal

•	A leaking radiator cap

Did you find and correct the condition?

Go to Step 21

Go to Step 6

Start the engine.
Place the blower motor 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 7

Observe the drive shaft of both air temperature actuators.
Adjust the air temperature switch.

Does the drive shaft of both air temperature actuators rotate?

Go to Step 8

Go to Step 9

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

•	A misaligned actuator on the air temperature door

•	Broken linkages or binding linkages

•	A broken air temperature door or a binding air temperature door

•	An obstruction that prevents the air temperature door from operating within the 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 21

Go to Heating Performance Diagnostic

Test the position signal circuit of the appropriate temperature actuator 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 21

Go to Step 10

Test the low reference circuit of the appropriate temperature actuator 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 21

Go to Step 11

Test the 5-volt reference circuit of the appropriate air temperature actuator for a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 21

Go to Step 12

Turn OFF the ignition.
Reconnect the appropriate temperature actuator.
Turn ON the ignition with the engine OFF.
Connect a test lamp between temperature door control A and temperature door control B circuits of the appropriate temperature actuator connector.
Place the temperature switch in the cold position.
Place the temperature switch in the hot position.

Does the test lamp illuminate in both positions?

Go to Step 21

Go to Step 13

Test the temperature door control A and temperature door control B circuits of the appropriate temperature actuator 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 21

Go to Step 14

Test the ignition 3 voltage circuit of the HVAC control module 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 15

Go to Step 17

Test the ground circuit of the HVAC control module 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 16

Go to Step 18

Inspect the appropriate air temperature door for a mechanical condition or for a condition that allows excessive travel of the door.

Did you complete the repair?

Go to Step 21

Inspect for poor connections at the harness connector of the appropriate 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 21

Go to Step 19

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 21

Go to Step 20

Important: Perform the calibration procedure for the air temperature actuator.

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

Did you complete the replacement?

Go to Step 21

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