Thermal Vacuum Switch: 4.2L
- Cool air cleaner intake air temperature to less than 40°F (4°C). Detach vacuum lines from TVS and connect a vacuum pump to "A" port of TVS. See Fig 1 .
- Apply vacuum to TVS. TVS should hold vacuum when its temperature is below 40°F (4°C). If not, replace TVS.
- Start engine and idle until air cleaner intake air temperature is above 55°F (13°C). TVS should not hold vacuum. If it does hold vacuum, replace TVS.