1973olds98

iam in the process of putting my 455 back together and was wondering what plugs into the heater control valve...Is it some sort of sensor..

Lady72nRob71

The heater valve screws into the rear right of the block. The big hose goes to the heater core and the tiny hose inlet on the valve is for the vacuum control hose. That hose would go to the heater controls. I think in 1973, vacuum applied = valve off.
Not sure if this helps, but I hope so...

Olds64

There is also an electric sensor that goes to the heater control valve. At least in my 71 98 there is. I'm not really sure what it is used for. There is a bung in one side of the valve where the sensor screws into.

Lady72nRob71

Does the car in question have the auto temp controls??
If so, thats a good explanation of an electrical sensor - I never have seen that...

rocketraider

The threaded port is for a coolant temperature sensor for Comfortron equipped cars. Most all the valves have the port since it was probably cheaper to have one p/n for all applications than different valves for each type of A/C.

Comfortron is designed to not operate until the car has warmed up sufficiently (coolant temp >120 degrees) to provide heat. The water valve sensor does this. Two wires to it, black with double white stripe at passenger rear of engine.

If car does not have Comfortron, the threaded port is not used.

1973olds98

ok the sensor part was what i was referring to..Mine does have it..i was just wondering what it was and how it works..

joe_padavano

The sensor is a temp sensor that should prevent the blower motor from coming on until the coolant warms up to prevent blowing cold air at the passengers.

Olds64

My car has the temp sensor. It might not be working properly because my blower no longer works. I was thinking I might have a vacuum leak as well. I need to check it out.

joe_padavano

Easy enough to test. Simply pull the connector off the temp sender, jumper across the terminals in the harness connector, and see if the fan runs. Alternately, check continuity at the sender terminals with the engine cold and again with the engine hot.

Olds64

I'm sorry, I don't understand. You say check continuity at the sender terminals; however, there is only one terminal on the temp sensor that attaches to the heater control valve.

joe_padavano

OOPs, sorry, I'm working off the later model cars that use the two-wire sender. In your case, check continuity to ground.

Olds64

Thanks!