Wagoneer L6-258 4.2L VIN C 2-bbl (1982)
EGR Temperature Sensor: Description and Operation
OPERATION
This switch is located at the coolant passage of the intake manifold (adjacent to oil filler tube) on a V8 engine, at the left side of the engine block
(formerly the drain plug location) on a six cylinder engine or in coolant passage at right rear of cylinder head on four cylinder engines. The outer
part of the switch is open and not used. The inner port is connected by a hose to the EGR fitting at the carburetor. The outer port is connected to
the EGR valve, or to the TVS on four cylinders.
When the coolant temperature is below 115° F (160° F on some vehicles), the center port of the switch is closed and no vacuum signal is applied
to the EGR valve, therefore, no exhaust gas will flow through the valve. When the coolant temperature reaches 115° F (160° F on some vehicles),
both the center and inner port of the switch are open and a vacuum signal is applied to the EGR valve. However, the vacuum signal to the EGR
valve is subject to regulation by low and high temperature signal modulators.
