GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 Canyon Pickup - 4WD 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Blower Motor Inoperative

Test Description

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

  1. The IGN 3 relay, HVAC A fuse and the blower motor are in a series circuit. The test lamp should illuminate if there is no concern with the series circuit.

    2.

  2. Probe the ground circuit of the blower motor switch in the HVAC control assembly.

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The blower motor is inoperative in all speed positions.

1

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

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

Does the blower motor operate in any speed position?

Go to Blower Motor Malfunction

Go to Step 3

3
  1. Turn OFF the ignition.
  2. Disconnect the blower motor.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the blower motor supply voltage circuit of the blower motor with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 4

4

Probe the HVAC A fuse with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 12

Go to Step 5

5
  1. Disconnect the ignition 3 relay.
  2. Probe the battery positive circuit of the ignition 3 relay with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 15

Go to Step 9

6
  1. Place the blower motor switch to the maximum speed position.
  2. Connect a test lamp between the blower motor supply voltage circuit and the blower motor high control circuit of the blower motor.

Does the test lamp illuminate?

Go to Step 13

Go to Step 7

7
  1. Connect the blower motor.
  2. Disconnect the HVAC control assembly.
  3. Connect a test lamp between the blower motor high control circuit of the HVAC control assembly and a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 10

8

Connect a test lamp between the ground circuit of the HVAC control assembly and battery positive voltage circuit.

Does the test lamp illuminate?

Go to Step 14

Go to Step 11

9

Repair the battery positive circuit of the ignition 3 relay for an open. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 18

--

10

Repair the blower motor high control circuit of the HVAC control assembly for an open. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 18

--

11

Test the ground circuit for an open and a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 14

12

Repair the blower motor supply voltage circuit of the blower motor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 18

--

13

Inspect for poor connections at the blower motor. 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 18

Go to Step 16

14

Inspect for poor connections at 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 18

Go to Step 17

15

Replace the ignition 3 relay.

Did you complete the replacement?

Go to Step 18

--

16

Replace the blower motor. Refer to Blower Motor Replacement in Heating Ventilation and Air Conditioning.

Did you complete the replacement?

Go to Step 18

--

17

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

Did you complete the replacement?

Go to Step 18

--

18

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2