For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The temperature cannot be adjusted, or the heating is insufficient.
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Turn the ignition ON, with the engine OFF.
2. Place the blower 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

3 | Does the blower motor operate at the desired speeds? | Go to Step 4 | Go to Blower Motor Malfunction
4 |

1. Start the engine.
2. Place the blower motor switch in the maximum speed position.
3. Lower the glove box off its upper attachments.
4. Observe the recirculation door.
5. Place the recirculation switch in the ON position.

Does the recirculation door move to the recirculation position?

Go to Step 5

Go to Air Recirculation Malfunction

5 | Place the blower motor switch to the OFF position. Does the A/C compressor operate? | Go to HVAC Compressor Clutch Does Not Disengage | Go to Step 6
6 | Inspect the cooling system for the following conditions:

• | A low coolant level

• | A loose radiator hose or heater hose

• | A kinked radiator hose or heater hose

• | A missing radiator cap pressure seal

• | A leaking radiator cap

Did you find and correct the condition?

Go to Step 9

Go to Step 7

7 | Perform the Heating Performance Diagnostic. Refer to Heating Performance Diagnostic . Did you find and correct the condition? | Go to Step 9 | Go to Step 8
8 | Inspect the air temperature door and linkage for the following conditions:

• | High effort to operate air temperature door

• | Broken or binding linkages or air temperature door

• | An obstruction that prevents the air temperature door from operating within it's 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 9

Go to High or Low Temperature Control Effort

9 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2