Vacuum System Test
WARNING: This page is about a different car, the 1998 Chevrolet Monte Carlo and 1998 Chevrolet Lumina. However, it is still accessible from the selected car via links, so may be relevant.
- Start engine and let idle. Check vacuum supply (Black vacuum hose) to vacuum/electric solenoid assembly. 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 on A/C-heater control panel 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 assembly.