The numbers below refer to the step numbers on the diagnostic table.
The test lamp should illuminate while trying to command the mode door in both directions.
Two voltage circuits supply the HVAC control assembly.
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 | |||||||||||
2 |
Is the blower motor OFF? | Go to Step 3 | Go to Blower Motor Malfunction | ||||||||||
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 Malfunction | ||||||||||
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 assembly controls except for the blower motor inoperative? | Go to Step 15 | Go to Step 6 | ||||||||||
6 |
Does the recirculation door move from the recirculation to the outside air position? | Go to Step 7 | |||||||||||
7 |
Does air flow sufficiently from the proper air distribution outlets for each selected mode position? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 8 | ||||||||||
8 | Inspect the air delivery system for the following conditions:
Did you find and correct the condition? | Go to Step 21 | Go to Step 9 | ||||||||||
9 | 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 10 | ||||||||||
10 | Test the position signal circuit of the mode actuator for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 21 | Go to Step 11 | ||||||||||
11 | Test the low reference circuit of the mode actuator for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 21 | Go to Step 12 | ||||||||||
12 | Test the 5-volt reference circuit of the appropriate mode actuator for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 21 | Go to Step 13 | ||||||||||
Does the test lamp illuminate in both positions? | Go to Step 17 | Go to Step 14 | |||||||||||
14 | Test the mode door control A and mode door control B circuits of the mode actuator for an open, a high resistance, a short to ground, or a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 21 | Go to Step 18 | ||||||||||
Test the voltage circuits of the HVAC control assembly for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 21 | Go to Step 16 | |||||||||||
16 | Test the ground circuit of the HVAC control assembly for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 21 | Go to Step 18 | ||||||||||
17 | Inspect for bad connections at the harness connector of the mode actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 21 | Go to Step 19 | ||||||||||
18 | Inspect for bad connections at the harness connector of the HVAC control assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 21 | Go to Step 20 | ||||||||||
19 | Replace the mode actuator. Refer to Mode Actuator Replacement . Did you complete the replacement? | Go to Step 21 | -- | ||||||||||
20 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | Go to Step 21 | -- | ||||||||||
21 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 8 |