The numbers below refer to the step numbers on the diagnostic table.
The test lamp should illuminate while trying to command the appropriate mode door in both directions.
Two ignition 3 voltage circuits supply the HVAC control module. Test the ignition 3 voltage circuit that does not supply the blower motor switch.
Check the connection by removing and securely reinstalling before replacement of the HVAC control is considered.
Step | Action | Yes | No | ||||||||||||
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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 | |||||||||||||
2 |
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 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 in Wiring Systems | 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 appropriate 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 appropriate 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 | Test the low reference circuit of the appropriate 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 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 to Wiring Repairs in Wiring Systems. 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 appropriate 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 21 | Go to Step 18 | ||||||||||||
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 21 | 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 21 | Go to Step 18 | ||||||||||||
17 | Inspect for bad connections at the harness connector of the appropriate 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 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 21 | Go to Step 20 | |||||||||||||
19 | Replace the appropriate mode actuator. Refer to Mode Actuator Replacement or Defroster Valve Actuator Replacement . Did you complete the replacement? | Go to Step 21 | -- | ||||||||||||
20 | Replace the HVAC Control module. Refer to HVAC Control Module 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 |