Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
DEFINITION: Improper air delivery.
| |||||||||
1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to | ||||||
2 |
Does air flow out of the selected HVAC outlet ducts? | Go to Step 4 | Go to Step 3 | ||||||
3 | 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 8 | Go to Step 4 | ||||||
4 | 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 19 | Go to Step 5 | ||||||
5 | 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 7 | Go to Step 6 | ||||||
6 | Repair the no vacuum condition. Is the repair complete? | Go to Step 19 | -- | ||||||
7 | 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 12 | Go to Step 9 | ||||||
8 |
Does the system lose vacuum after turning OFF the engine? | Go to Step 9 | Go to Step 12 | ||||||
9 | 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 10 | Go to Step 11 | ||||||
10 | Repair or replace the collapsed or leaking vacuum line. Is the repair complete? | Go to Step 19 | -- | ||||||
11 | Replace the vacuum reservoir tank. Refer to . Vacuum Tank Replacement Is the repair complete? | Go to Step 19 | -- | ||||||
12 | Using an external vacuum source, apply vacuum to the appropriate vacuum line at the connector to the HVAC vacuum control assembly. Refer to . HVAC Schematics Does the actuator retract? | Go to Step 18 | Go to Step 13 | ||||||
13 | 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 10 | Go to Step 14 | ||||||
14 |
Did the actuator hold a vacuum? | Go to Step 15 | Go to Step 17 | ||||||
15 | With the actuator disconnected, inspect the door for binding. Does the door move freely? | Go to Step 17 | Go to Step 16 | ||||||
16 | Repair the binding door. Refer to the appropriate repair:
Is the repair complete? | Go to Step 19 | -- | ||||||
17 | Replace the vacuum actuator. Refer to the appropriate repair: Is the repair complete? | Go to Step 19 | -- | ||||||
18 | Replace the HVAC vacuum control assembly. Refer to . Heater and Air Conditioning Control Replacement Is the repair complete? | Go to Step 19 | -- | ||||||
19 | Cycle the HVAC controls through all modes to verify proper operation. Did you find and correct the condition? | System OK | Go to Step 2 | ||||||
