Coolant Temperature Switch

Fig. 4 Switches & sensors location. V8 engine:

On V8 engines the coolant switch is located on the front of the intake manifold, Fig. 4. 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 except there is no control of canister purging.