GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

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

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

Go to Step 5

Go to Step 2

2

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

Does the door bind?

Go to Step 4

Go to Step 3

3

  1. Inspect for control binding.
  2. Remove the heater control unit. Refer to Control Assembly Replacement .
  3. Disconnect the control cable from the heater control unit in order to determine if the cable or the control unit is binding.

Does the control cable bind?

Go to Step 7

Go to Step 6

4

  1. Remove the heater case. Refer to Heater Case Replacement .
  2. Inspect the door seal for proper installation.
  3. Inspect for a bent door shaft.
  4. Inspect for a warped heater case.
  5. Replace the door seal, or replace the heater case.

Is the repair complete?

Go to Step 8

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5

  1. Route the control cables in order to avoid interference. Ensure the proper clearance between the cables and the instrument panel components.
  2. Replace the control cables if the cables are kinked. Refer to the necessary procedures:
  3. • Temperature Control Cable Replacement
    • Vent Control Cables Replacement

Is the repair complete?

Go to Step 8

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6

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

Is the repair complete?

Go to Step 8

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7

Replace the corresponding control cable. Refer to the necessary procedures:

    • Temperature Control Cable Replacement
    • Vent Control Cables Replacement

Is the repair complete?

Go to Step 8

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8

Perform the function test. Refer to Function Test .

Is the repair complete?

System OK

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