Control Assembly: Testing and Inspection

NOTE: The vacuum system supplies engine vacuum, by way of an intake manifold vacuum line, to operate the heating and ventilation control servos. The vacuum system is tested by checking for servo operation and vacuum at different control head settings. The servos are best reached by removing the instrument panel.

TABLE FOR CONTROL BUTTON SETTINGS.:

NOTE: No response from any servos at any control head setting indicates that there is a problem either with vacuum supply or with the control head.





- Check vacuum supply by removing the vacuum supply hose from the four-way connector with the engine running. No vacuum at the hose indicates a fault in the hose to the intake manifold. Vacuum at the hose when it is removed indicates a fault at the control head.
- If only one or two servos fail to respond to a control head setting, remove the hose from the malfunctioning servo(s) and check for vacuum. No vacuum indicates a faulty control head or vacuum hose. Vacuum indicates a faulty servo.