For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the entire HVAC System Check performed? | -- | Go to Step 2 | Go to HVAC System Check
2 |

1. Turn the auxiliary blower switch to the REAR position.
2. Disconnect the auxiliary heater-A/C control connector C1.
3. Place the ignition switch in the RUN position.
4. Using a J 39200 , probe between the auxiliary heater-A/C control connector C1 terminal 4 and ground.
5. Move the temperature control knob from hot to cold, and then cold to hot.

Does the measured voltage vary between approximately 1 and 12 volts?

1-12 V

Go to Step 3

Go to Step 4

3 | Using a J 39200 , probe between the auxiliary heater-A/C control connector C1 terminal 1 and ground. Is the measured voltage within the specified values? | 9-14 V | Go to Step 5 | Go to Step 6
4 | Repair the poor connection or open in CKT 733 between S252 and the auxiliary heater-A/C control connector C1 terminal 4. Is the repair complete? | -- | Go to Step 15 | --
5 | Using a J 39200 , probe between the auxiliary heater-A/C control connector C1 terminal 6 and B+. Is the measured voltage within the specified values? | 9-14 V | Go to Step 8 | Go to Step 7
6 | Repair the poor connection or open in circuit 641 between the auxiliary heater-A/C control connector C1 terminal 1 and S345. Is the repair complete? | -- | Go to Step 15 | --
7 | Repair the open in CKT 850 between the auxiliary heater-A/C control connector C1 terminal 6 and S403. Is the repair complete? | -- | Go to Step 15 | --
8 |

1. Check for a poor connection at the auxiliary heater-A/C control connector C1 terminal 5.
2. Check for a short to ground or voltage in CKT 955.
3. If OK, replace the auxiliary heater-A/C control. Refer to Control Assembly Replacement - Auxiliary in Side Trim Panel or Control Assembly Replacement - Auxiliary in Overhead Console .

Was replacement of the auxiliary heater-A/C control necessary?

--

Go to Step 15

Go to Step 9

9 | Repair the poor connection or short to ground in CKT 955. Is the repair complete? | -- | Go to Step 10 | --
10 | Using a J 39200 , probe between the temperature valve actuator connector terminal 10 and ground. Is the measured voltage within the specified values? | 9-14 V | Go to Step 11 | Go to Step 12
11 | Using a J 39200 , probe between the auxiliary temperature valve actuator connector terminal 7 and B+. Is the voltage within the specified values? | 9-14 V | Go to Step 13 | Go to Step 14
12 | Repair the poor connection or open in CKT 641 between the auxiliary temperature valve actuator connector terminal 10 and S345. Is the repair complete? | -- | Go to Step 15 | --
13 | Replace the auxiliary temperature valve actuator. Refer to Temperature Actuator Replacement - Auxiliary . Is the repair complete? | -- | Go to Step 15 | --
14 | Repair the open in CKT 850 between the auxiliary temperature valve actuator connector terminal 7 and S403. Is the repair complete? | -- | Go to Step 15 | --
15 |

1. Turn the ignition switch to the OFF position.
2. Reconnect all connectors/components removed.

Have all the repairs been made?

--

Go to HVAC System Check

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