GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you perform the HVAC System Check?

Go to Step  2

Go to the HVAC System Check

2

  1. Disconnect the blower motor connector.
  2. Connect a test lamp across the blower motor connector.
  3. Start the engine.
  4. Turn the blower speed selector switch to any position except OFF.

Does the test lamp light?

Go to Step  14

Go to Step  3

3

Test for an open in the BLK/WHT wire between the blower motor and the blower motor resistor.

Is an open present?

Go to Step  16

Go to Step  4

4

Test for an open in the BLK wire between the blower motor and the HTR relay in fuse and relay block 3.

Is an open present?

Go to Step  15

Go to Step  5

5

Test that the HTR relay is open between terminals 4 and 5 and that there is continuity between terminals 4 and 2. Refer to Fuse and Relay Block 3 in Wiring Systems.

Did the relay test OK?

Go to Step  6

Go to Step  13

6

  1. Remove the HTR relay from fuse and relay block 3.
  2. Start the engine.
  3. Test for battery voltage at terminal 1.

Is battery voltage present?

Go to Step  8

Go to Step  7

7

Test for an open in the RED/BLU wire between fuse and relay block 3 and the multifunction alarm module, including junction block 3.

Is an open present?

Go to Step  15

Go to Step  17

8

  1. Stop the engine.
  2. Install the HTR relay.
  3. Move the blower speed selector switch to the OFF position.
  4. Disconnect blower speed selector switch.
  5. Start the engine.
  6. Test for battery voltage at terminal 3 of the blower speed selector switch.

Is battery voltage present?

Go to Step  9

Go to Step  10

9

Test for an open in the WHT/BLK wire between the blower speed selector switch terminal 1 and G204.

Is an open present?

Go to Step  15

Go to Step  11

10

Test for an open in the BLU/ORN wire between fuse and relay block 3 and the blower speed selector switch.

Is an open present?

Go to Step  15

Go to Step  13

11

  1. Stop the engine.
  2. Test for an open between terminals 3 and 1 of the blower speed selector switch with the switch at each speed level.
  3. Move the blower speed selector switch to the MEDIUM 1 position.
  4. Test for an open between terminals 3 and 4 of the blower speed selector switch.
  5. Move the blower speed selector switch to the MEDIUM 2 position.
  6. Test for an open between terminals 3 and 8 of the blower speed selector switch.
  7. Move the blower speed selector switch to the HIGH position.
  8. Test for an open between terminals 3 and 5 of the blower speed selector switch.

Is an open present in any of the above tests?

Go to Step  12

Go to Step  13

12

Replace the blower speed selector switch. Refer to Blower Switch Replacement .

Is the repair complete?

Go to the HVAC System Check

--

13

Replace the heater relay. Refer to Blower Motor Relay Replacement .

Is the repair complete?

Go to the HVAC System Check

--

14

Replace the blower motor. Refer to Blower Motor and Fan Replacement .

Is the repair complete?

Go to the HVAC System Check

--

15

Repair the open. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to the HVAC System Check

--

16

Repair the open in the BLK/WHT wire between the blower motor and S200. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to the HVAC System Check

--

17

Replace the multifunction alarm module. Refer to Multifunction Alarm Module Replacement in Instrument Panel, Gauges and Console.

Is the repair complete?

Go to the HVAC System Check

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