Step | Action | Yes | No |
|---|---|---|---|
1 |
Does air flow out of the selected HVAC outlet ducts? | Go to Step 3 | Go to Step 2 |
2 | Did the customer concern mention that the air discharges out the correct ducts at first, but then changes during higher engine RPM? | Go to Step 7 | Go to Step 3 |
3 | With the engine running, cycle the HVAC controls through all the modes. Does the air come out of the selected outlet ducts? | Go to Step 18 | Go to Step 4 |
4 | With the engine running, take a vacuum reading at the manifold vacuum port that supplies vacuum to the HVAC vacuum control assembly. Is there engine vacuum? | Go to Step 6 | Go to Step 5 |
5 | Repair the no vacuum condition. Is the repair complete? | Go to Step 18 | -- |
6 | Take a vacuum reading at the vacuum supply line at the HVAC vacuum control assembly. Is the vacuum reading the same as the engine vacuum? | Go to Step 11 | Go to Step 8 |
7 |
Does the system lose vacuum after turning OFF the engine? | Go to Step 8 | Go to Step 11 |
8 | Inspect for leaking or collapsed vacuum lines between the engine manifold vacuum port and the HVAC vacuum control assembly. Are the vacuum lines leaking? | Go to Step 9 | Go to Step 10 |
9 | Repair or replace the collapsed or leaking vacuum line. Is the repair complete? | Go to Step 18 | -- |
10 | Replace the vacuum reservoir tank. Is the repair complete? | Go to Step 18 | -- |
11 | Using an external vacuum source, apply vacuum to the appropriate vacuum line at the connector to the HVAC vacuum control assembly. Does the actuator retract? | Go to Step 17 | Go to Step 12 |
12 | Inspect for leaking or collapsed vacuum lines between the actuator and the connector to the HVAC vacuum control assembly. Are the vacuum lines leaking? | Go to Step 9 | Go to Step 13 |
13 |
Did the actuator retract? | Go to Step 14 | Go to Step 16 |
14 | With the actuator disconnected, inspect the door for binding. Does the door move freely? | Go to Step 16 | Go to Step 15 |
15 | Repair the appropriate binding door. Is the repair complete? | Go to Step 18 | -- |
16 | Replace the appropriate vacuum actuator. Is the repair complete? | Go to Step 18 | -- |
17 | Replace the HVAC vacuum control assembly. Is the repair complete? | Go to Step 18 | -- |
18 | Cycle the HVAC controls through all modes to verify proper operation. Did you correct the condition? | System OK | -- |
