Join Date: Nov 2000
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Intake manifold heater wiring question
I'm cleaning up my wiring harness and re-installing an 84 intake manifold with the electric heater. I believe I've found the old relay that once activated the manifold heater, it's got an orange wire to the manfold heater (or at least it has the right type of spade tip on it to go there), and among two power sources, a green wire that grounds the relay thru a sensor that has a single round lug on top. Short green wire, so it likely went to the intake manifold. Previous posts mention the green wire as well.
My question is, which sensor on the intake manifold was the green wire hooked up to? There is a red top sensor that screws into the aluminum (but not the water jacket), which seems electrically an open at room temperature, and a black one that went into the coolant passage, and is connected to ground at room temperature. I believe if I had to pick between the two,only the black grounded one would make sense, but maybe it's neither? I'm working with old parts here, and I wouldn't rule out the possibility that either switch could be defective. Can anyone point me in the right direction as to which sensor properly grounds out this relay until the motor heats up, and that the orange wire was the one that went to the intake manifold heater? Is this a separate relay from the choke relay that was previously discussed?
BTW, my tests on the bench of that intake manifold heater show it to be more than a token source of heat. In my cold unheated garage, in 20 seconds that heater was too hot to touch on the pin side that is interior of the intake manifold. In 60 seconds the whole assembly was too hot to touch. Someone said 20 + amps. So that could be some 280 watts of heat on a small area, albeit cooled by incoming air and fuel. I have to believe it would be effective.