Vent

0.2 V

Bi-Level

3.0 V

Floor

6.0 V

Mix-Blend

9.0 V

Defrost

12.0 V

Schematic Reference : HVAC Schematics

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

Did you review the HVAC operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

1. Turn ON the ignition, with the engine OFF.
2. Place the blower motor switch in the OFF position.

Is the blower motor in the OFF position?

Go to Step 3

Go to Blower Motor Always On

Place the blower motor switch in each speed position.

Does the blower motor operate in any of the speed positions?

Go to Step 4

Go to Blower Motor Inoperative

Does the blower motor operate at the desired speeds?

Go to Step 5

Go to Blower Motor Malfunction

Are all of the HVAC control assembly controls except for the blower motor inoperative?

Go to Step 14

Go to Step 6

1. Place the blower motor switch in the maximum speed position.
2. Place the mode switch in each mode position.

Does the air flow 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 7

Inspect the air distribution system for the following: conditions

Did you find and correct the condition?

Go to Step 21

Go to Step 8

Inspect the mode door and the mode actuator for the following conditions.

Did you find and correct the condition?

Go to Step 21

Go to Step 9

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

Does the test lamp illuminate?

Go to Step 10

Go to Step 18

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 21

Go to Step 11

11

1. Measure the voltage from the mode door control circuit of the mode actuator to a good ground.
2. Place the mode switch in each mode position while observing the voltage. Refer to the Test Description.

Does the voltage measure near the specified values for each mode position?

Go to Step 16

Go to Step 13

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

Did you find and correct the condition?

Go to Step 21

Go to Step 17

13

Test the ignition 3 voltage circuit of the HVAC control assembly 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 21

Go to Step 14

Test the ground circuit of the HVAC control assembly 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 21

Go to Step 15

Test the OFF blower motor control circuit of the HVAC control assembly 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 21

Go to Step 17

Inspect for poor 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 21

Go to Step 19

Inspect for poor connections at the harness connector of the HVAC control assembly. 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 21

Go to Step 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 21

--

Replace the mode actuator. Refer to Mode Actuator Replacement .

Did you complete the replacement?

Go to Step 21

--

Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement .

Did you complete the replacement?

Go to Step 21

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 7