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Makes 🢒 Chevrolet 🢒 2002 🢒 Chevy Suburban - 4WD 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Auxiliary Blower Motor Always On

Auxiliary Blower Motor Always On W/Sunroof or Heat Only

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step checks for continuous operation of the auxiliary blower motor.

    2.

  2. This step determines if the malfunction is in the auxiliary HVAC control assembly.

    3.

  3. This step tests for a short to ground in the control side of the system. It is easiest to perform this step by disconnecting the auxiliary blower motor resistor assembly connector C1 and the auxiliary HVAC control assembly. Test each auxiliary blower motor speed control circuit for continuity to a known good ground.

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

DEFINITION: The auxiliary blower motor is on while the auxiliary blower motor switch is in the OFF position.

1

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

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

2

  1. Turn ON the ignition, with the engine OFF.
  2. Place the auxiliary blower motor switch to the OFF position.

Is the blower motor OFF?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the auxiliary HVAC control assembly.
  3. Turn ON the ignition, with the engine OFF.

Is the blower motor OFF?

Go to Step 6

Go to Step 4

4

Test each auxiliary blower motor speed control circuit between the auxiliary blower motor resistor assembly and the auxiliary HVAC control assembly for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Inspect for poor connections at the harness connector of the auxiliary blower motor resistor 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 9

Go to Step 8

6

Inspect for poor connections at the harness connector of the auxiliary 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 9

Go to Step 7

7

Replace the auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Front or Auxiliary Heater and Air Conditioning Control Replacement - Rear .

Did you complete the replacement?

Go to Step 9

--

8

Replace the auxiliary blower motor resistor assembly. Refer to Auxiliary Blower Motor Resistor Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the replacement?

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2

Auxiliary Blower Motor Always On W/O Sunroof

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step tests for auxiliary blower motor operation in the OFF setting.

    2.

  2. The rear auxiliary HVAC control assembly should not operate with the front auxiliary blower motor switch in the OFF position.

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

DEFINITION: The auxiliary blower motor is on while the auxiliary blower motor switch is in the OFF position.

1

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

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

2

  1. Turn ON the ignition, with the engine OFF.
  2. Place the front auxiliary blower motor switch to the OFF position.
  3. Place the rear auxiliary blower motor switch to the OFF position.

Does the auxiliary blower motor operate?

Go to Step 4

Go to Step 3

3

Important: The front auxiliary blower motor switch must remain in the OFF position.

Place the rear auxiliary blower motor switch to the maximum speed position.

Does the auxiliary blower motor operate?

Go to Step 8

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

4
  1. Turn OFF the ignition.
  2. Disconnect the rear auxiliary HVAC control assembly.
  3. Turn ON the ignition, with the engine OFF.

Does the auxiliary blower motor continue to operate?

Go to Step 5

Go to Step 6

5

Test each auxiliary blower motor speed control circuit between the auxiliary blower motor resistor assembly and the rear auxiliary HVAC control assembly for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 11

6
  1. Turn OFF the ignition.
  2. Connect the rear auxiliary HVAC control assembly.
  3. Disconnect the front auxiliary HVAC control assembly.
  4. Turn ON the ignition, with the engine OFF.

Does the auxiliary blower motor operate?

Go to Step 7

Go to Step 13

7

Test each auxiliary blower motor speed control circuit between the front auxiliary HVAC control assembly and the rear auxiliary HVAC control assembly for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 12

8
  1. Turn OFF the ignition.
  2. Disconnect the front auxiliary HVAC control assembly.
  3. Turn ON the ignition, with the engine OFF.

Does the auxiliary blower motor continue to operate?

Go to Step 9

Go to Step 13

9

Test the rear auxiliary enable control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 10

10

Test auxiliary blower motor control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 14

11

Inspect for poor connections at the harness connector of the auxiliary blower motor resistor 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 19

Go to Step 16

12

Inspect for poor connections at the harness connector of the rear auxiliary 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 19

Go to Step 17

13

Inspect for poor connections at the harness connector of the front auxiliary 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 19

Go to Step 15

14

Inspect for poor connections at the harness connector of the auxiliary HVAC control processor. 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 19

Go to Step 18

15

Replace the front auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Front .

Did you complete the replacement?

Go to Step 19

--

16

Replace the auxiliary blower motor resistor assembly. Refer to Auxiliary Blower Motor Resistor Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the replacement?

Go to Step 19

--

17

Replace the rear auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Rear .

Did you complete the replacement?

Go to Step 19

--

18

Replace the auxiliary HVAC control processor. Refer to Auxiliary HVAC Control Processor Replacement .

Did you complete the replacement?

Go to Step 19

--

19

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2