Coolant Temperature Switch

On V6-238 engines, the coolant switch is located on front left side of intake manifold. It operates by supplying a signal to the computer when the engine coolant temperature is below 150~ F. This information is required to prevent a change in air fuel ratio until engine operation temperature is reached. In addition, when the engine temperature reaches 150° F., the computer will switch the air pump injection from upstream to downstream into the exhaust system and will allow the charcoal canister to purge.