For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you review the HVAC operation and perform the necessary inspections? | -- | Go to Step 2 | Go to Symptoms - HVAC Systems - Manual
2 |

1. Turn the ignition switch to the RUN position.
2. Use the J 39200 Digital Multimeter (DMM) in order to measure the voltage between terminal C of the heater A/C control assembly connector C2 and ground.

Does the voltage measured equal the specified value?

B+

Go to Step 3

Go to Step 4

3 |

1. Disconnect the heater A/C control assembly connector C2.
2. Use the J 39200 DMM in order to measure the voltage between terminal C and terminal K of the heater A/C control assembly connector C2.

Does the voltage measured equal the specified value?

B+

Go to Step 5

Go to Step 6

4 | Use the J 39200 DMM in order to measure the voltage between terminal A11 of the underhood wiring harness junction block connector C3 and ground. Does the voltage measured equal the specified value? | B+ | Go to Step 7 | Go to Step 8
5 |

1. Reconnect the heater A/C control assembly connector C2.
2. Use the J 39200 DMM in order to backprobe the heater A/C control assembly connector C2.
3. Measure the voltage between terminal G and ground.
4. Turn the temperature control from COLD to HOT.

Does the voltage vary within the specified range?

1-12 V

Go to Step 9

Go to Step 10

6 | Repair the open in CKT 251 between the heater A/C control assembly and ground splice pack G204. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | System OK | --
7 | Repair the open in CKT 41 between the underhood wiring harness junction block and the heater A/C control assembly. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | System OK | --
8 | Replace the underhood wiring harness junction block. Refer to Underhood Fuse Block Replacement in Engine Electrical. Is the repair complete? | -- | System OK | --
9 |

1. Disconnect the air temperature actuator connector.
2. Connect the J 39200 DMM between terminal 8 of the air temperature actuator connector and ground.
3. Turn the temperature control from COLD to HOT.

Does the voltage vary within the specified range?

1-12 V

Go to Step 11

Go to Step 12

10 | Replace the heater A/C control assembly. Refer to LINK Control Assembly Replacement . Is the repair complete? | -- | System OK | --
11 | Connect the J 39200 DMM between terminal 10 of the air temperature actuator connector and ground. Does the voltage measured equal the specified value? | B+ | Go to Step 13 | Go to Step 14
12 | Repair the open in CKT 733 between the air temperature actuator and the heater A/C control assembly. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | System OK | --
13 | Use the J 39200 DMM in order to measure the voltage between terminal 7 and terminal 10 of the air temperature actuator connector. Does the voltage measured equal the specified value? | B+ | Go to Step 15 | Go to Step 16
14 | Repair the open in CKT 41 between the underhood wiring harness junction block and the air temperature actuator. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | System OK | --
15 | Replace the air temperature actuator. Refer to LINK Temperature Actuator Replacement . Is the repair complete? | -- | System OK | --
16 | Repair the open in CKT 251 between the air temperature actuator and ground splice pack G204. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | System OK | --