GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did the HVAC Blower Controls System Check bring you here?

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Go to Step 2

Go to HVAC Blower Controls System Check

2

Inspect the HTR-A/C fuse 12 at the IP fuse block.

Is the fuse operational?

--

Go to Step 4

Go to Step 3

3

  1. Locate and repair the overload.
  2. Replace the HTR-A/C fuse 12.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

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4

Inspect the RR Heat A/C fuse at the underhood fuse/relay center.

Is the fuse operational?

--

Go to Step 6

Go to Step 5

5

  1. Locate and repair the overload.
  2. Replace the RR Heat A/C fuse.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

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6

  1. Disconnect the rear air conditioning (A/C) blower motor.
  2. Place the ignition switch in the RUN position.
  3. Place the rear A/C switch in the HIGH position.
  4. Connect a test lamp J 35616-200 from the rear A/C blower motor CKT 1052 (ORN) at the blower motor to ground.

Did the test lamp light?

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Go to Step 7

Go to Step 8

7

Connect a test lamp J 35616-200 between CKT 1052 (ORN) and CKT 1250 (BLK) at the rear A/C blower motor.

Did the test lamp light?

--

Go to Step 9

Go to Step 11

8

  1. Disconnect the A/C relay (rear).
  2. Connect a test lamp J 35616-200 from CKT 742 (RED) cavity A9 at the A/C relay (rear) to ground.

Did the test lamp light?

--

Go to Step 12

Go to Step 13

9

Inspect for a poor connection at the rear A/C blower motor.

Does a poor connection exist?

--

Go to Step 6

Go to Step 14

10

Repair the poor connection.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

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11

Repair the open in CKT 1250 (BLK) between the rear A/C motor and ground G404.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

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12

Connect a test lamp J 35616-200 from CKT 141 (BRN) cavity A7 at the A/C relay (rear) to ground.

Did the test lamp light?

--

Go to Step 15

Go to Step 16

13

Repair the open in CKT 742 (RED) between the rear heat - A/C relay (rear) (underhood fuse-relay center) and the rear heat - A/C maxi fuse M2 (underhood fuse-relay center).

Is the repair complete?

--

Go to HVAC Blower Controls System Check

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14

Replace the rear A/C blower motor.

Refer to Auxiliary Blower Motor and Fan Replacement .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

15

Connect a test lamp J 35616-200 from CKT 141 (BRN) cavity A7 to CKT 850 (BLK) cavity B9 at the A/C relay (rear).

Did the test lamp light?

--

Go to Step 17

Go to Step 18

16

Repair the open in CKT 141 (BRN) between the A/C relay (rear) and the instrument panel fuse block.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

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17

  1. Reconnect the A/C relay (rear).
  2. Use a test lamp J 35616-200 in order to backprobe from the A/C relay (rear) CKT 1923 (ORN) cavity B7 to ground.

Did the test lamp light?

--

Go to Step 19

Go to Step 20

18

Repair the open in CKT 850 (BLK) between the A/C relay (rear) and ground G104.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

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19

Use a test lamp J 35616-200 in order to backprobe from the rear A/C switch connector CKT 1923 (ORN) cavity G to ground.

Did the test lamp light?

--

Go to Step 21

Go to Step 22

20

Replace the A/C relay (rear).

Refer to Blower Motor Relay Replacement .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

21

Use a test lamp J 35616-200 in order to backprobe from the rear A/C switch CKT 1052 (ORN) cavity A to ground.

Did the test lamp light?

--

Go to Step 23

Go to Step 24

22

Repair the open in CKT 1923 (ORN) between the rear A/C switch and the A/C relay (rear).

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

23

Use a test lamp J 35616-200 in order to backprobe from the rear A/C resistor pack CKT 1052 (ORN) cavity B to ground.

Did the test lamp light?

--

Go to Step 26

Go to Step 25

24

Replace the rear A/C switch. Refer to Accessory Switch Replacement in Instrument Panel Gauges and Console.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

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25

Repair the open in CKT 1052 (ORN), CKT 1072 (LT BLU) and CKT 1176 (YEL) between the rear A/C switch and the rear A/C resistor pack.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

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26

Repair open in CKT 1052 (ORN) between the rear A/C resistor pack and the rear A/C blower motor.

Is the repair complete?

--

Go to HVAC Blower Controls System Check

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