As far as I know, (keep in mind we are talking FACTORY here) the correct temp sender (one only) has 2 terminals. My cars, plus, the wiring diagram supports this. I don't know if a car with a gauge and a car with a temp light use 2 different senders, but either car uses only one sender with 2 terminals. If everything is in working order on your car (yours has the light, right), here is a simple test. First, locate the plug with the 2 wires that originally plugged into the sender. Get a short piece of wire for a jumper. Start and let the engine run. Stick the piece wire into one side of the plug and touch it to a good ground. Have someone look at your dash to see if the red temp light comes on. If it doesn't, then ground the other wire. As you look at the end of the terminals on the sender, they form a V. The wire for the temp light SHOULD BE V< on this side of the V. The terminal on this side >V, SHOULD go to the TCS relay. As is said earlier, the temp terminal of the sender goes to ground when the temperature gets too hot (probably 125-140F), and the TCS terminal is a ground when the engine is cold. A simple test for this terminal is to use a test light. Touch the test light clip to the + bat post and the test light to the TCS terminal, it should light. Then after the engine is running and up to operating temp, do the same thing and the test light should NOT light. TOO EASY.
I have relocated the sender on my 70 to the intake manifold because the headers get too hot for the plastic connector. And I have completely disconnected/removed ALL my TCS stuff to help clean up under the hood.
Hope this helps.
All of the above should also apply to a car with a gauge. Except with a gauge, when you ground the temp wire, the gauge should go to full hot.
I WOULD ENCOURAGE EVERYONE TO INVEST IN A WIRING DIAGRAM. They are too cheap and are a very helpful tool.
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Tom Parsons
[This message has been edited by DZAUTO (edited 01-08-2000).]