Ventilation Air Flow System

Ventilation Air Flow System
1. With the ignition switch ON and the blower motor switch set to position 4 for maximum air flow, check the air flow patterns resulting from the position settings of the air flow selector lever as shown in the chart. Verify that they conform to the specified air flow patterns as listed (shown in the diagrams following the chart):










2. If air flow patterns do not conform to the specified patterns, repair, adjust, or replace the outlet doors or components as required.






3. With the ignition switch ON and the blower motor switch set to position 4 for maximum air flow, change the function control lever setting from MAX A/C to any other position. Verify that the air movement conforms to the specified patterns as shown in the chart:
4. If RECIRC/Fresh air does not conform to the specified patterns, proceed with the following tests:
a. Disconnect the vacuum control switch connector and check for vacuum with the engine running.
b. If no vacuum is present, check the vacuum supply for leaks or damage. Replace the vacuum check valve, vacuum lines, or the A/C vacuum reservoir tank as necessary.
c. Check the vacuum control switch by applying vacuum to one port using Rotunda Vacuum Tester 021-00014 or equivalent. Vacuum should hold when the air flow selector lever knob is in any position except the MAX A/C (with A/C) or RECIRC (without A/C) position. Vacuum should release when the switch is opened by moving the air flow selector lever knob to the MAX A/C (with A/C) or RECIRC (without A/C) position. Replace the switch if vacuum does not hold or release properly.
d. Disconnect the vacuum control motor and apply vacuum with a vacuum tester. The A/C air inlet door should open as vacuum is applied and close as vacuum is released. If the A/C air inlet door does not move properly, check the linkages for kinks or damage. Repair or replace linkages as necessary. Otherwise, replace the vacuum control motor.
e. Check the vacuum line between the vacuum control switch and the vacuum control motor for leaks or kinks. Repair or replace the line as necessary.
5. Disassemble the following components of the ventilation system for inspection as required, and remove any foreign material causing air flow blockage:
- A/C blower motor
- A/C evaporator housing
- Recirculation inlet
- Fresh inlet
- Main air duct (no A/C)
- Evaporator (with A/C)
- Heater core inlet side
- Air outlets at floor, panel, and defroster
6. If air flow is inadequate in any position, adjust the A/C air inlet door, defrost/floor control door, temperature control door, or vent function control door as required. Otherwise, return to the Pinpoint Tests.