GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Inspect Fuse 14 in the fuse block .

Is the Fuse open?

--

Go to Step 2

Go to Step 3

2

Repair the short to ground in CKT 40 (ORN).

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

3

  1. Place the ignition switch in the OFF position.
  2. Place the Heater - A/C control in the VENT position.
  3. Disconnect the blower motor relay.
  4. Place the ignition switch in the RUN position.
  5. Place the blower switch in the HI position.
  6. Use a test lamp to backprobe between the blower motor relay harness connector terminal C 2 CKT 52 (ORN) and ground.

Does the test lamp light?

--

Go to Step 4

Go to Step 8

4

Use a test lamp to backprobe between the blower motor relay harness connector terminal  A2 and ground.

Does the test lamp light?

--

Go to Step 5

Go to Step 11

5

Use a test lamp, connected to B+, to backprobe the blower motor relay harness connector terminal  A1.

Does the test lamp light?

--

Go to Step 6

Go to Step 7

6

Replace the blower motor relay.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

7

Locate and repair a poor connection or an open in CKT 150 (BLK) between the blower motor relay connector and ground G 205:

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

8

  1. Place the ignition switch in the OFF position.
  2. Reconnect the blower motor relay.
  3. Disconnect the heater A/C connector C 1.
  4. Use a test lamp, connected to B+, to backprobe the heater A/C control connector C 1 terminal E circuit 52 (ORN) .

Does the test lamp light?

--

Go to Step 9

Go to Step 10

9

Locate and repair a poor connection or an open in circuit 52 (ORN).

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

10

Replace the heater - A/C control. Refer to Control Assembly Replacement .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

11

Locate and repair a poor connection or an open in CKT 40 (ORN).

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--