Electronic Climate Control
Inspection and VerificationVacuum System Diagnosis Tools Required:
^ Rotunda Vacuum Tester 021-00014
To test the EATC vacuum system, start the engine and press the function buttons slowly, one at a time. A momentary hiss should be heard as each button is
pressed from one position to another, indicating that vacuum is available at the control assembly. A continuous hiss at the control assembly indicates a major leak somewhere in the system. It does not necessarily indicate that the leak is at the control assembly.
If a momentary hiss cannot be heard as each function button is pressed, check for a kinked, pinched, or disconnected vacuum supply hose. Also, inspect the check valve between the intake manifold and the vacuum reservoir to ensure it is working properly.