Vacuum System Test
WARNING: This page is about a different car, the 1996 Pontiac Grand Prix, 1996 Oldsmobile Cutlass Supreme, 1996 Chevrolet Monte Carlo, and 1996 Chevrolet Lumina. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Perform OUTLET AIRFLOW INCORRECT test before performing this test.
- Start engine. Check vacuum supply to solenoid box (Black vacuum hose). Vacuum should be about 18 in. Hg and remain at 18 in. Hg when engine is turned off.
- Check each vacuum actuator by disconnecting vacuum hose and applying vacuum directly to actuator. Repair or replace actuator as necessary. See Fig 1.
- Reconnect all vacuum and electrical connections. Run engine and cycle through all modes while observing vacuum actuators. Check for vacuum to actuators by observing vacuum actuator position. When vacuum is applied, actuator will retract.
- If an actuator retracts when it should not, replace A/C-heater control panel. If an actuator does not retract, check for vacuum leaks, collapsed vacuum hoses or binding valves. If components are okay, replace vacuum/electric solenoid box.