Test Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

12: The measured voltage should be near the specified values for each mode position.

14: Two ignition 3 voltage circuits supply the HVAC control module. Test the ignition 3 voltage circuit that does not supply the blower motor switch.

Air Delivery Improper

Step	Action	Value	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 HVAC Diagnostic System Check?	-	Go to Step 2	Go to Diagnostic System Check - HVAC Systems - Manual
2	Turn ON the ignition, with the engine OFF. Place the blower motor switch in the OFF position. 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 any speed position?	-	Go to Step 4	Go to Blower Motor Inoperative
4	Does the blower motor operate in each speed position?	-	Go to Step 5	Go to Blower Motor Malfunction
5	Are all of the HVAC control module controls except for the blower motor inoperative?	-	Go to Step 14	Go to Step 6
6	Place the blower motor switch in the maximum speed position. Place the mode switch in the vent position. Place the recirculation switch in the ON position. Observe the recirculation door. Place the outside air switch in the ON position. Does the recirculation door move from the recirculation to the outside air position?	-	Go to Step 7	Go to Air Recirculation Malfunction
7	Place the blower motor switch in the maximum speed position. Place the mode switch in each mode position. Does air flow sufficiently from the proper air distribution outlets for each selected mode position?	-	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 8
8	Inspect the air delivery system for the following conditions: A dirty HVAC air filter, if applicable An obstruction to the airflow Air leaks Misaligned air ducts Did you find and correct the condition?	-	Go to Step 23	Go to Step 9
9	Inspect the mode door and the mode actuator for the following conditions: A misaligned mode actuator Refer to Mode Actuator Replacement . Broken or binding linkages or mode door An obstruction that prevents the mode actuator from operating within the full range of motion Missing seals to the mode door Misaligned seals to the mode door Did you find and correct the condition?	-	Go to Step 23	Go to Step 10
10	Turn OFF the ignition. Disconnect the mode actuator. Turn ON the ignition, with the engine OFF. Probe the ignition 3 voltage circuit of the mode actuator with a test lamp that is connected to a good ground. Does the test lamp illuminate?	-	Go to Step 11	Go to Step 20
11	Test the ground circuit of the mode actuator for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 23	Go to Step 12
12	Turn OFF the ignition. Reconnect the mode actuator. Turn ON the ignition with the engine OFF. Measure the voltage from the mode door control circuit of the mode actuator to a good ground. Observe the control circuit voltage of the mode door. Place the mode switch in each mode position. Does the voltage measure near the specified values for each mode position?	Vent: 0.2V, Bi-Level: 3.1V, Floor: 5.0V Mix-Blend: 8.9V, Defrost: 11.8V	Go to Step 18	Go to Step 13
13	Test the mode door control circuit of the mode actuator for an open, a high resistance, a short to ground, or a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 23	Go to Step 19
14	Test the ignition 3 voltage circuit of the HVAC control module for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 23	Go to Step 15
15	Test the battery positive voltage circuit of the HVAC control module for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 23	Go to Step 16
16	Test the ground circuit of the HVAC control module for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 23	Go to Step 17
17	Test the off blower motor control circuit of the HVAC control module for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 23	Go to Step 19
18	Inspect for bad connections at the harness connector of the mode actuator. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 23	Go to Step 21
19	Inspect for bad connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 23	Go to Step 22
20	Repair the ignition 3 voltage circuit of the mode actuator. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	-	Go to Step 23	-
21	Replace the mode actuator. Refer to Mode Actuator Replacement . Did you complete the replacement?	-	Go to Step 23	-
22	Replace the HVAC Control module. Refer to HVAC Control Module Replacement (Buick) or HVAC Control Module Replacement (Pontiac) . Did you complete the replacement?	-	Go to Step 23	-
23	Operate the system in order to verify the repair. Did you correct the condition?	-	System OK	Go to Step 8