Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you review the HVAC system operation and perform the necessary inspections? | -- | Go to Step 2 | Go to Symptoms |
2 | Verify that the temperature control is inoperative. Does the temperature control operate normally? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
3 |
Did the voltage vary smoothly and continuously within the range specified? | 1 V to 12 V | Go to Step 5 | Go to Step 4 |
4 | Did the voltage remain at or near the battery voltage regardless of the temperature knob position? | -- | Go to Step 23 | Go to Step 10 |
5 | Connect a test lamp between CKT 341 (BRN) wire and ground at the air temperature valve sensor and motor. Did the test lamp light? | -- | Go to Step 7 | Go to Step 6 |
6 | Repair the open in CKT 341 (BRN) wire between the instrument panel (IP) fuse block and the air temperature valve sensor and motor. Is the wire repair complete? | -- | Go to Step 28 | -- |
7 | Connect a self-powered test lamp between CKT 1850 (BLK) wire and ground at the temperature valve sensor and motor. Did the test lamp light? | -- | Go to Step 8 | Go to Step 9 |
8 | Replace the air temperature valve sensor and motor. Refer to Temperature Actuator Replacement in Heating, Ventilation and Air Conditioning. Is the replacement complete? | -- | Go to Step 28 | -- |
9 | Repair the open in CKT 1850 (BLK) wire. Is the wire repair complete? | -- | Go to Step 28 | -- |
10 | Connect a test lamp between CKT 341 (BRN) wire cavity A connector C3 at the heater and AC controller and ground. Did the test lamp light? | -- | Go to Step 20 | Go to Step 11 |
11 | Inspect HVAC I fuse 21. Is HVAC I fuse 21 open? | -- | Go to Step 13 | Go to Step 12 |
12 | Repair the open in CKT 341 (BRN) wire. Is the wire repair complete? | -- | Go to Step 28 | -- |
13 |
Did the test lamp light? | -- | Go to Step 14 | Go to Step 15 |
14 | Repair the short to ground in CKT 341 (BRN) wire. Is the wire repair complete? | -- | Go to Step 28 | -- |
15 | Connect a self-powered test lamp between CKT 733 (LT BLU) wire cavity B connector C3 at the heater and A/C Controller and ground. Did the test lamp light? | -- | Go to Step 16 | Go to Step 17 |
16 | Repair the short to ground in CKT 733 (LT BLU) wire. Is the wire repair complete? | -- | Go to Step 28 | -- |
17 | Connect a digital multimeter across terminals A and C of connector C3 at the heater and A/C controller and measure the resistance. Is the resistance less than the specified value? | 1.0 ohms | Go to Step 18 | Go to Step 19 |
18 | Replace the heater and A/C controller. Refer to Control Assembly Replacement . Is the replacement complete? | -- | Go to Step 28 | -- |
19 | Repair the intermittent short to ground in CKT 341 (BRN) wire. Is the wire repair complete? | -- | Go to Step 28 | -- |
20 | Connect a digital multimeter between CKT 733 (LT BLU) wire cavity B of C3 and CKT 733 (LT BLU) wire cavity 8 of the air temperature valve sensor and motor connector. Is the resistance less than or equal to the specified value? | 0.5 ohms | Go to Step 21 | Go to Step 22 |
21 | Replace the heater and A/C controller. Refer to Control Assembly Replacement . Is the replacement complete? | -- | Go to Step 28 | -- |
22 | Repair the open or the high resistance in CKT 733 (LT BLU) wire. Is the wire repair complete? | -- | Go to Step 28 | -- |
23 |
Did the test lamp light? | -- | Go to Step 24 | Go to Step 25 |
24 | Connect a self-powered test lamp between CKT 1850 (BLK) and ground at the air temperature valve sensor. Did the test lamp light? | -- | Go to Step 27 | Go to Step 26 |
25 | Repair the open or the high resistance in CKT 1050 (BLK) wire. Is the wire repair complete? | -- | Go to Step 28 | -- |
26 | Repair the open in CKT 1850 and ground. Is the repair complete? | -- | Go to Step 28 | -- |
27 | Replace the heater and A/C controller. Refer to Control Assembly Replacement . Is the replacement complete? | -- | Go to Step 28 | -- |
28 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 3 |
