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Looking around spark plugs, I found that on passenger side I have the TCS temp switch which seems not to be connected. The switch has two connections, one has the wire disconnected.
This is the picture from the ASM manual.
What is it?
Transmission Controlled Spark is part of the emissions system of the car. Mine no longer exists. When I bought the car, I had the same sensor on and hooked up but no other parts of the TCS system were on the car. When I put in a new engine wiring harness, all of those connections are tucked away.
This is from 7T1vette on another TCS question:
TCS is an emissions item only. With it active, the timing is retarded at idle (vacuum is blocked so that vacuum advance can on the dist is not operational until throttle is depressed). It only serves to run your engine hotter at low speeds (which burns more hydrocarbons...but does no good for your engine). If you want the car to "look" factory correct, leave the equipment on the car but fix it so that it is non-functional. Otherwise, put that stuff in a bag and store it somewhere.
The TCS switch has two terminals the original harness jumped the the terminals together and connected near the a/c evaporator a single green wire conector.
Mark