Vacuum System Testing

Fig.3 Vacuum Circuit Test:

Vacuum Circuits:

To locate a vacuum leak, disconnect 7-way vacuum connector behind the heater-A/C control panel.

Connect the calibrated vacuum hose probe to each port in the vacuum harness connector. After each connection is made, the test gauge should return to calibrated setting. If all circuits function properly, replace heater-A/C control. If not, determine the color of the vacuum circuit that is leaking. To determine vacuum line colors, refer to the Vacuum Circuits chart for the heater and manual A/C units. Disconnect the vacuum actuator at the other end of the circuit. Instrument panel removal may be necessary to gain access to some components. Block the end of the disconnected vacuum line. The test gauge should return to calibrated setting. If not, that circuit has a leak and must be repaired or replaced. If test gauge returns to calibrated setting, the vacuum actuator must be replaced.