# 1968 LeMans Temperature Sensor/Sender



## BaDaBooM (Feb 8, 2017)

Hello everyone!

I am busy restoring my 1968 LeMans with a 350 and cannot find the temp sender/sensor. I have the gauge not the light but the temp wire was connected like shown in the attached pic which is not correct.

Any pictures and advise would be highly appreciated!

Thanks

BaDaBooM


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## BearGFR (Aug 25, 2008)

Ames Performance should have them.
Why do you say the connection isn't correct? The connection for both a temperature light and a temperature gauge consists of just one wire on the engine harness, and it's usually green in color.

Bear


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## BaDaBooM (Feb 8, 2017)

Hey

Haha, the wire is actually green. When I bought the car the previous guys sprayed the car with all the wiring in, cleaned the over spray up on the wiring in the meantime.

It is currently connected to the TCS from what I can understand as there are 3 prongs on it and the gauge is staying on cold, here is what I could find.

That is the transmission controlled spark coolant temp switch, which is located in the rear of the passenger side cylinder head. The "TCS" system controlled the vacuum advance through a solenoid mounted towards the rear of the intake manifold - for emission control purposes. The solenoid in turn was switch on or off depending upon vehicle speed (TH350 and TH400 equipped cars) or gear selection (3 or 4 speed manual transmission equipped cars). This switch you have pictured was an override to allow vacuum advance under all conditions only when the coolant temperature was well above normal.

GM part number is 6490384 and the AC-Delco part number is G1868. Both are long discontinued and no aftermarket parts were ever available.


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