Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: Auxiliary air temperature can not be adjusted.

1

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

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

Does the HVAC control assembly operate and provide sufficient cooling?

Go to Step 3

Go to Too Hot in Vehicle

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

Does the heater auxiliary blower motor operate at all?

Go to Step 4

Go to Auxiliary Blower Motor Inoperative

Does the auxiliary blower motor operate correctly for each speed position?

Go to Step 5

Go to Auxiliary Blower Motor Malfunction

5

1. Start the engine.
2. Place the auxiliary heater blower motor switch in the OFF position.
3. Run the engine to achieve normal operating temperature.

Are the auxiliary heater hoses or auxiliary heater core hot?

Go to Step 6

Go to Step 9

6

Disconnect the vacuum hose from the hot water shut off valve.

Is there vacuum present at the hot water shut off valve vacuum hose?

Go to Step 7

Go to Vacuum Control System Diagnostic

7

1. Turn OFF the ignition.
2. Disconnect the hot water shut-off solenoid.
3. Connect a test lamp between the heater water control solenoid control circuit of the hot water shut-off valve solenoid and a good ground.
4. Turn ON the ignition, with the engine OFF.
5. Place the auxiliary heater blower motor switch in the OFF position.

Does the test lamp illuminate?

Go to Step 8

Go to Step 9

Test the heater water control solenoid control circuit of the hot water shut-off valve solenoid 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 13

Go to Step 10

Inspect for poor connections at the harness connector of the hot water shut-off valve solenoid. 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 13

Go to Step 11

Inspect for poor connections at the harness connector of the auxiliary heater blower motor switch. 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 13

Go to Step 12

Replace the hot water shut-off valve. Refer to Heater Water Shutoff Valve Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the replacement?

Go to Step 13

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Replace the auxiliary heater blower motor switch. Refer to Heater Control Blower Switch Replacement .

Did you complete the replacement?

Go to Step 13

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2