Air Delivery Improper - Auxiliary. GMC Truck Envoy

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For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2002 🢒 Envoy - 2WD 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Air Delivery Improper - Auxiliary

Air Delivery Improper - Auxiliary With Body Type VIN 3

Step

Action

Value(s)

Yes

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

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

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

Turn ON the ignition, with the engine OFF.
Place the blower motor switch in the maximum position.
Place the mode switch in the defrost position.
With a scan tool, observe the Rear HVAC parameter in the Heating and Air Conditioning data list.

Does the scan tool indicate that the Rear HVAC parameter displays Disabled?

Go to Step 3

Go to Step 22

Place the front mode switch in the floor position.
With a scan tool, observe the Rear HVAC parameter in the Heating and Air Conditioning data list.

Does the scan tool indicate that the Rear HVAC parameter displays Enabled?

Go to Step 4

Go to Step 22

Turn ON the headlamps.
Place the instrument panel dimmer switch in the brightest position.
Turn ON the auxiliary HVAC control module.

Does the power indicator of the auxiliary HVAC control module illuminate?

Go to Step 5

Go to Step 7

Place the auxiliary mode switch in each position.

Is the airflow sufficient from the correct auxiliary outlets in each mode?

Go to Step 6

Go to Step 11

Place the front mode switch in the defrost position.

Is there airflow from the auxiliary outlets?

Go to Step 15

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

Turn OFF the ignition.
Disconnect the auxiliary HVAC control module.
Turn ON the ignition with the engine OFF.
Probe the ignition 3 voltage circuit of the auxiliary HVAC control module with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 23

Test the ground circuit of the auxiliary HVAC control module for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 9

Probe the auxiliary HVAC enable control circuit of the auxiliary HVAC control module with a test lamp that is connected to battery positive voltage.

Does the test lamp illuminate?

Go to Step 10

Go to Step 21

Test the auxiliary HVAC enable control circuit of the auxiliary HVAC control module for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 22

Turn OFF the ignition.
Disconnect the auxiliary mode actuator.
Turn ON the ignition, with the engine OFF.
Probe the ignition 3 voltage circuit of the auxiliary mode actuator with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 12

Go to Step 24

Measure the voltage from the auxiliary mode door control circuit of the auxiliary mode actuator to a good ground.
Place the auxiliary mode switch in each position.

Does the voltage measure near the specified values?

3-5 V FLOOR

7-9 V BI-LEVEL

11-13 V PANEL

Go to Step 13

Go to Step 14

Test the ground circuit of the auxiliary mode actuator for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 19

Test the auxiliary mode door control circuit of the auxiliary mode actuator for an open, a high resistance, a short to ground or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 21

Does the power indicator illuminate on the auxiliary HVAC control module?

Go to Step 16

Go to Step 18

Turn OFF the ignition.
Disconnect the auxiliary HVAC control module.
Turn ON the ignition, with the engine OFF.
Place the front mode switch in the defrost position.
Measure the voltage from the auxiliary HVAC enable control circuit to battery positive voltage.

Does the voltage measure near the specified value?

B+

Go to Step 21

Go to Step 17

Test the auxiliary HVAC enable control circuit of the auxiliary HVAC control module for an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 22

Measure the voltage from the auxiliary mode door control circuit of the auxiliary mode actuator to a good ground.
Turn OFF the auxiliary HVAC control module.

Does the voltage measure near the specified value?

0 V

Go to Step 19

Go to Step 21

Inspect the auxiliary mode door and the auxiliary mode actuator for the following :

•	Misaligned auxiliary mode actuator

•	Broken or binding linkages or auxiliary mode door

•	Obstruction that prevents the recirculation actuator from operating within its full range of motion

•	Missing seals to the auxiliary mode door

•	Misaligned seals to the auxiliary mode door

Did you find and correct the condition?

Go to Step 28

Go to Step 20

Inspect for poor connections at the harness connector of the auxiliary mode actuator. 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 28

Go to Step 25

Inspect for poor connections at the harness connector of the auxiliary HVAC control module. 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 28

Go to Step 26

Inspect for poor connections at the harness connector of the HVAC control module. 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 28

Go to Step 27

Repair the ignition 3 voltage circuit of the auxiliary HVAC control module. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

Repair the ignition 3 voltage circuit of the auxiliary mode actuator. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

Replace the auxiliary mode actuator. Refer to Auxiliary Mode Valve Actuator Replacement .

Did you complete the replacement?

Go to Step 28

Replace the auxiliary HVAC control module. Refer to Auxiliary Heater and Air Conditioning Control Module Replacement .

Did you complete the replacement?

Go to Step 28

Replace the HVAC control module. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

Go to Step 28

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2

Air Delivery Improper - Auxiliary With Body Type VIN 6

Step	Action	Yes	No
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The auxiliary mode doors cannot be adjusted.
1	Did you perform the HVAC Diagnostic System Check?	Go to Step 2	Go to Diagnostic System Check - HVAC Systems - Automatic
2	Recalibrate actuators. Refer to Actuator Recalibration . Turn ON the ignition, with the engine OFF. With a scan tool, observe the DTC list in Rear HVAC/RSA. Does the scan tool display DTC B0145, B0428, or B3531?	Go to Diagnostic Trouble Code (DTC) List	Go to Step 3
3	Turn ON the ignition, with the engine OFF. Place the front auxiliary blower motor switch in each speed position. Does the front auxiliary blower motor operate in any of the speed positions?	Go to Step 4	Go to Auxiliary Blower Motor Inoperative
4	Does the auxiliary blower motor operate at the desired speed?	Go to Step 5	Go to Auxiliary Blower Motor Malfunction
5	Turn ON the ignition, with the engine OFF. Place the front auxiliary blower motor switch in the Rear position. With a scan tool, observe the Console Mode Door actual and the Mode Door Actual parameter in the Rear HVAC/RSA data list. Place the auxiliary mode switch from the floor position to the upper outlets position. Does both the Console Mode Door and the Mode Door Actual parameters count value change?	Go to Step 8	Go to Step 6
6	Inspect for poor connections at the harness connector of the auxiliary HVAC control module. 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 8	Go to Step 7
7	Replace the auxiliary HVAC control module. Refer to Auxiliary Heater and Air Conditioning Control Module Replacement . Did you complete the replacement?	Go to Step 8	--
8	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 2