GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1998 🢒 Silhouette Ext. 🢒 Body and Accessories 🢒 Wiring Systems 🢒 Temperature Control Inoperative - Front and Rear

Step

Action

Value(s)

Yes

No

1

Was the entire HVAC System Check performed?

--

Go to Step 2

Go to HVAC System Check

2

Were you sent here for a poor cooling concern of the passenger compartment?

--

Go to Step 3

Go to Step 4

3

Does the A/C compressor clutch engage when the A/C button is depressed?

--

Go to Step 5

Go to HVAC Compressor Clutch Does Not Engage

4

Before proceeding with the following table, check and make sure that:

    • the engine is reaching normal operating temperature.
    • both upper and lower radiator hoses have become hot.
    • both inlet and outlet heater hoses have become hot.
    • the cooling system is operating normally.

Is the cooling system operating normally?

--

Go to Step 5

Go to Heating Insufficient

5
  1. Disconnect the heater-A/C control connector C2.
  2. Turn the ignition switch to the RUN position.
  3. Connect a test light from the heater-A/C control connector C2 terminal E and ground.

Is the test light on?

--

Go to Step 6

Go to Step 7

6

Backprobe with a test light between the heater-A/C control connector C2 terminal C and ground.

Is the test light on?

--

Go to Step 8

Go to Step 9

7

Repair a poor connection or open in CKT 640 between the heater-A/C control connector C2 terminal E and S202.

Is the repair complete?

--

Go to Step 16

--

8

Backprobe with a test light between the heater-A/C control connector C2 terminal K and B+.

Is the test light on?

--

Go to Step 10

Go to Step 11

9

Repair the poor connection or open in CKT 241 between the heater-A/C control connector C2 terminal C and S264.

Is the repair complete?

--

Go to Step 16

--

10
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the electric slave actuator connector.
  3. Disconnect the auxiliary heater-A/C control connector C1.
  4. Using a J 39200 , check for continuity in CKT 733 between the heater-A/C control connector C2 terminal G and the electric slave actuator terminal 8.
  5. Using a J 39200 , check for continuity in CKT 733 between the heater-A/C control connector C2 terminal G and the auxiliary heater-A/C control connector C1 terminal 4.

Is there continuity for both tests?

--

Go to Step 12

Go to Step 13

11

Repair the poor connection or open in CKT 150 between the heater-A/C control connector C2 terminal K and S213.

Is the repair complete?

--

Go to Step 16

--

12

Using a J 39200 , check for continuity in CKT 733 between the heater-A/C control connector C2 terminal G and ground.

Is circuit 733 shorted to ground?

--

Go to Step 14

Go to Step 15

13

Repair the poor connection or open in CKT 733.

Is the repair complete?

--

Go to Step 16

--

14

Repair the short to ground in CKT 733.

Is the repair complete?

--

Go to Step 16

--

15

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

Is the repair complete?

--

Go to Step 16

--

16
  1. Turn the ignition switch to the OFF position.
  2. Reconnect all connectors/components disconnected.

Have all repairs been made?

--

Go to HVAC System Check

--