GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Functional Check performed?

--

Go to Step 2

Refer to Function Test

2

Inspect the control cables from the heater control unit to the heater case and the blower case. Inspect for any improper routing, kinks, and interference.

Do any of the control cables have improper routing, kinks, or interference?

--

Go to Step 7

Go to Step 3

3

  1. Disconnect the control cable from the door that causes the binding.
  2. Cycle the door manually.

Does the door bind?

--

Go to Step 5

Go to Step 4

4

Inspect for control binding.

Does control binding exist?

--

Go to Step 6

Go to Step 12

5

  1. Remove the heater case. Refer to Blower Motor and Fan Replacement .
  2. Inspect the door seal for proper installation.

Is the door seal properly installed?

--

Go to Step 9

Go to Step 8

6

  1. Remove the heater control unit. Refer to Control Assembly Replacement .
  2. Disconnect the control cable from the heater control unit and inspect for binding.

Does control binding exist?

--

Go to Step 10

Go to Step 11

7

  1. Route the control cables in order to avoid interference.
  2. Replace any control cables that are kinked. Refer to the following:
  3. • Temperature Control Cable Replacement
    • Vent Control Cables Replacement

Is the action complete?

--

Go to Step 13

--

8

Repair the door seal as necessary.

Is the action complete?

--

Go to Step 13

--

9

Inspect for a bent door shaft or a warped heater case.

Does a bent door shaft or warped heater case exist?

--

Go to Step 13

--

10

Replace the heater control unit. Refer to Control Assembly Replacement .

Is the action complete?

--

Go to Step 13

--

11

Replace the corresponding control cable. Refer to the following:

    • Temperature Control Cable Replacement
    • Vent Control Cables Replacement

Is the action complete?

--

Go to Step 13

--

12

Reinstall the control cable and inspect for proper clearance to the IP components. Repair as necessary.

Is the action complete?

--

Go to Step 13

--

13

Perform the functional test. Refer to Function Test .

Is the action complete?

--

System OK

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