GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 Century 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Temperature Control Inoperative

Step

Action

Value(s)

Yes

No

1
  1. Check the HVAC fuse in the fuse block.
  2. Ensure the HVAC fuse is open.

Is the HVAC fuse open?

--

Go to Step 2

Go to Step 3

2

Repair a short to ground in circuit 41(BRN). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 16

--

3
  1. Turn the ignition switch to the RUN position.
  2. Install a Digital Multimeter (DMM) .
  3. LH Inoperative: Backprobe between the heater-A/C control harness connector C2 terminal G (circuit 1199) and ground.
  4. RH Inoperative: Backprobe between the heater-A/C control harness connector C2 terminal E (circuit 1199) and ground.
  5. Move the temperature control knob from WARM to COOL and COOL to WARM.

Does the measured voltage vary within the specified value?

1-12 V

Go to Step 4

Go to Step 5

4
  1. Disconnect the inoperative electric actuator connector.
  2. Connect a DMM, between the inoperative electric actuator harness connector terminal 10 (circuit 41) and ground.

Is the measured voltage within the specified value?

9-14 V

Go to Step 6

Go to Step 7

5
  1. Disconnect the heater-A/C control harness connector C2.
  2. Connect a DMM, between the heater-A/C control connector C2 terminal C (circuit 41) and ground.
  3. Turn the ignition switch to the RUN position.

Is the measured voltage within the specified value?

9-14 V

Go to Step 13

Go to Step 12

6

Connect a DMM, between the inoperative electric actuator harness connector between terminal 10 (circuit 41) and terminal 7 (circuit 1450).

Is the measured voltage within the specified value?

9-14 V

Go to Step 8

Go to Step 9

7

Repair a poor connection or an open in circuit 41 (BRN) between the inoperative electric actuator harness connector terminal 10 and S 233. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems..

Is the repair complete?

--

Go to Step 16

--

8
  1. Connect a DMM, between the inoperative electric actuator harness connector terminal 8 and ground.
  2. Turn the ignition switch to the RUN position.
  3. Move the temperature control knob from WARM to COOL and COOL to WARM.

Does the measured voltage vary within the specified value?

1-12 V

Go to Step 16

Go to Step 11

9

Repair a poor connection or an open in circuit 1450 between the inoperative electric actuator harness connector terminal 7 and G 200. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 16

--

10
  1. Test for a poor connection at the inoperative electric actuator. Repair or replace, if necessary.
  2. Test for a binding air temperature valve. Repair or replace, if necessary.
  3. Replace the inoperative electric actuator. Refer to Temperature Actuator Replacement (LH) .

Is the repair complete?

--

Go to Step 16

--

11
  1. RH Inoperative: Repair a poor connection or an open in circuit 1199 (DK BLU).
  2. LH Inoperative: Repair a poor connection or an open in circuit 1236 . Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 16

--

12

Repair a poor connection or an open in circuit 41 (BRN) between S 233 and the heater-A/C control harness connector C2 terminal C. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 16

--

13
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the inoperative electric actuator connector.
  3. LH Inoperative: Test for a short to ground in circuit 1199 (DK BLU).
  4. RH Inoperative: Test for a short to ground in circuit 1236.

Is the circuit shorted to ground?

--

Go to Step 14

Go to Step 15

14
  1. LH Inoperative: Repair a short to ground in circuit 1199 (DK BLU).
  2. RH Inoperative: Repair a short to ground in circuit 1236. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete and have you retested the system?

--

Go to Step 16

--

15

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

Is the repair complete and have you retested the system?

--

Go to Step 16

--

16

Verify that the system operates properly?

Does the system operate properly?

--

System OK

Go to Symptoms