GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 DeVille 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Air Delivery Improper

Test Description

The number below refers to the step number on the diagnostic table.

  1. Refer to the following table of specified values.

Mode Position

Value

Defrost

0 Counts

Mix-Blend

65 Counts

Floor

110 Counts

Bi-Level

220 Counts

Vent

255 Counts

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: Air does not flow correctly from the air distribution outlets.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
  1. Turn ON the ignition, with the engine OFF.
  2. Turn OFF the HVAC controls.

Is the blower motor OFF?

Go to Step 3

Go to Blower Motor Always On

3

Place the blower motor switch in each speed position.

Does the blower motor operate in each speed position?

Go to Step 4

Go to Blower Motor Inoperative

4

Does the blower motor operate at the desired speeds?

Go to Step 5

Go to Blower Motor Malfunction

5
  1. Place the blower motor switch in the maximum speed position.
  2. Place the mode switch in the BI-LEVEL position.
  3. Alternately, place recirculation switch in the outside air and recirculation positions.

Does the recirculation door move from the recirculation position to the ambient air position?

Go to Step 6

Go to Air Recirculation Malfunction

6
  1. Install a scan tool.
  2. Recalibrate the motors. Refer to Actuator Recalibration .
  3. With a scan tool, observe the current DTC list in Instrument Panel Module.

Does the scan tool display any DTCs?

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

Go to Step 7

7

Place the mode switch in each mode position.

Does the air flow from the correct air distribution outlets in each selected mode position?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 8

8
  1. With the scan tool, observe the Selected Air Mode parameter in the Instrument Panel Module data list.
  2. Place the mode switch in each mode position.

Does the scan tool display the correct state for each selected mode?

Go to Step 9

Go to Step 10

9

  1. With the scan tool, observe the Htr./Def./A/C Dr. Commanded parameter in the Instrument Panel Module data list.
  2. Place the mode switch in each mode position.

Does the scan tool indicate that the Htr./Def./A/C Dr. Commanded parameter is near the specified value in each mode position? Refer to the test description for this step.

Go to Step 11

Go to Step 10

10

Inspect for poor connections at the harness connector of the HVAC control module (IPM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 12

11

Inspect and the air distribution system for the following conditions:

    • A restricted passenger compartment air filter
    • An obstruction restricting air flow
    • Air leaks
    • Misaligned ducts

Did you find and correct the condition?

Go to Step 13

--

12

Replace the IPM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 13

--

13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3