GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Corvette 🢒 Body and Accessories 🢒 Data Link Communications 🢒 Temperature Control Inoperative

Temperature Control Inoperative <<C60>>

Step

Action

Value(s)

Yes

No

DEFINITION: Checks the inputs to the temperature door motor.

1

Were you sent here from the HVAC System Check (C60)?

--

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 temperature door motor connector.
  2. Turn the ignition switch to the ON position.
  3. Connect a DMM between terminal 10 of the temperature door motor connector and a known good ground.

Is the voltage within the specified values?

10.0-14.0V

Go to Step 9

Go to Step 6

6

Check the HVAC MiniFuse® #18 for an open circuit.

Is the fuse open?

--

Go to Step 8

Go to Step 7

7

Locate and repair an open or a high resistance in CKT 41.

Is the repair complete?

--

Go to HVAC System Check

--

8

Locate and repair a short to ground in CKT 41.

Is the repair complete?

--

Go to HVAC System Check

--

9
  1. Connect the DMM between ground and terminal 7 of the temperature door motor connector.
  2. Measure CKT 150 for continuity to ground.

Is CKT 150 continuous to ground?

--

Go to Step 11

Go to Step 10

10

Locate and repair an open or a high resistance in CKT 150 between the temperature door motor connector and G201.

Is the repair complete?

--

Go to HVAC System Check

--

11
  1. Connect the DMM between terminal 8 of the temperature door motor connector and a known good ground.
  2. Turn the ignition switch to the ON position.
  3. Turn the temperature control knob from hot to cold, and cold to hot.

Does the voltage vary within the specified values?

1.0-12.0V

Go to Step 12

Go to Step 13

12
  1. Check for a poor connection at the temperature door motor.
  2. Check for a binding air temperature valve.
  3. If OK, replace the temperature door motor.

Is the repair complete?

--

Go to HVAC System Check

--

13
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the HVAC Control Assembly connector C1.
  3. Connect the DMM between terminal 8 of the temperature door motor connector and a known good ground.
  4. Measure CKT 1316 for continuity to ground.

Is CKT 1316 continuous to ground?

--

Go to Step 14

Go to Step 15

14

Locate and repair a short to ground in CKT 1316.

Is the repair complete?

--

Go to HVAC System Check

--

15
  1. Connect the DMM between the temperature door motor connector terminal 8 and the HVAC Control Assembly connector C1 terminal G.
  2. Measure CKT 1316 for continuity between these two connectors.

Is CKT 1316 continuous between the temperature door motor connector terminal 8 and the HVAC Control Assembly connector C1 terminal G?

--

Go to Step 16

Go to Step 17

16

Replace the HVAC Control Assembly.

Refer to Control Assembly Replacement .

Is the repair complete?

--

Go to HVAC System Check

--

17

Locate and repair an open or a high resistance in CKT 1316.

Is the repair complete?

--

Go to HVAC System Check

--