[ultraman]

I have an original 72 4bbl intake with a 3 prong temp sender, is it a hot and cold lamp sender? How could I check?Thanks everyonefor all the help I have recieved.I before e except after c wierd.

["QUICK-SILVER"]

72 had a bunch of new electric controlled emissions stuff going on.
Cars with a temp light had the three prong sender. One terminal is for the temp light. The other two where for early smog control. Mostly controlled timing when cold by cutting off the vacuum advance. The engine and under hood had several other switches and gadgetts that went along with it.

The temp light grounds through the sensor to the intake (when over heated), like regular one prong sensors.
The other two made and broke contact between each other with temp changes.

Testing, if it's good: The temp light terminal shoud be the only one that makes contact with the housing if you can boil it hot enough. If you had/have the original plugin for it, the dark green wire would be on the correct terminal.

And that's all I know to tell you.
Be careful if you try heating it up.

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[ultraman]

thanks quicksilver,I thought it could be an emissions sender.I will remove it and ck it like you suggested.