Schematic Reference: HVAC Schematics

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

1

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

2

1. Turn ON the ignition, with the engine OFF.
2. Place the mode switch in any position except OFF.
3. 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

Does the blower motor operate at the desired speeds?

Go to Step 4

Go to Blower Motor Malfunction

1. Start the engine.
2. Place the blower motor switch in the maximum speed position.
3. Place the mode switch in the recirculation position.

Does the recirculation door move to the recirculation position?

Go to Step 5

Go to Vacuum Control System Diagnostic

5

Place the HVAC control assembly in the OFF position.

Does the A/C compressor operate?

Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 6

Inspect the cooling system for the following conditions:

Did you find and correct the condition?

Go to Step 11

Go to Step 7

7

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

Did you find and correct the condition?

Go to Step 11

Go to Step 8

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

Did you find and correct the condition?

Go to Step 11

Go to Step 9

Inspect for poor connections at the harness connector of the HVAC control assembly. 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 11

Go to Step 10

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

Did you complete the replacement?

Go to Step 11

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2