Here are three pictures of a connector that is V shaped with a green wire coming out of what appears to be a tan wire. I have no air conditioning on the 71 Corvette. Can anybody tell me what this wire is for? I can’t even find anywhere to plug it in.

 

Ok. I’ll guess by looking at the top pic the green wire should go to the horn. If they are connected together as it looks like they are they would be connected to both horns.

 

Ok. I take it back. I thought they were 2 Plugs you were holding together. Not for the horns. I guess it’s time for me to turn off the ipad and watch the fireworks. Sorry.

 

Those go to the two terminals on the sending unit in your right hand cylinder head.

 

Ahhjhh! The infamous TCS connector. Most folks have NO IDEA what that wiring does. It appears to loop back on itself. Guess what? IT DOES!!!

That wire and connector attach to the TCS temperature sensor in the right side cylinder head (as you already know...but others may not). That sensor has TWO switches in it. One of them detects when the engine has warmed up adequately; the other switch detects when the engine is 'hotter' than the TCS system would like it to be (not overtemp for the engine). The TCS system was utilized on base engines to attain EPA emissions requirements WITHOUT the installation of an A.I.R. pump on the engine. Basically, it allowed the engine to run with ignition timing 'retarded' at idle and at lower speeds, under normal acceleration. It did this by switching the vacuum source going to the distributor vacuum advance can from MANIFOLD vacuum (what the engine would like to see all of the time) to PORTED/TIMED vacuum (what the EPA wanted, so that excess hydrocarbons would be burned in a "hot" combustion chamber). The vacuum switch on the driver's side of the carburetor was the unit that "chose" which vacuum source to send to the distributor. The temp sender and wiring you are asking about made the decision of whether that TCS system was to operate as intended OR whether it should be defeated and allow manifold vacuum to the advance can.
The conditions which would allow TCS to be defeated were: engine not warmed up enough to justify TCS operation, AND enigne TOO WARM to justify TCS operation. EITHER of those conditions would 'kill' the TCS system and revert engine operation back to "normal". The temp sender switch(es) and the 'crazy' little connector and wiring you have made that happen.

So now you know. But, you should also know that the TCS system may be "green", but it does nothing else good for your engine. Many folks choose to remove it completely; some folks rig it so that, with a simple hose swap, the system can remain as 'stock TCS' operation OR to normal non-TCS operation, with manifold vacuum always going to the distributor can. Very few folks leave it as is on their car...unless it is a "show" vehicle trying to win "original vehicle" awards.

 

Thank you for the detailed explanation that really makes more sense to me now.

 

I just noticed that this connector on my engine is smashed. I was fairly confident it was exactly what you said it was...BUT I couldn't find it anywhere to confirm. My factory assembly guide got delivered today and is sitting on my porch to replace my Chilton guide. So that might have it listed.

Any idea where to get a replacement connector?

 

Is the TCS sensor still in the passenger side cyl head? If not then I would tape it up out of the way. If you want a replacement connector is probably going to have to come from a salvage yard. That connector shouldnt be hard to find though. It was probably used on millions of GM cars/trucks

 

...so...if I search TCS sensor I can find it, but if I spelled out TCS it wouldnt come up...ugh.

 

As mentioned, you aren't losing anything by defeating the TCS system on your car...or by removing it altogether. You just need to route "manifold" vacuum directly to the advance can on the distributor and "call it a day'.

If you connector is smashed and not usable, but the sensor is OK, you might check with LectricLimited.com to see if they carry replacements.

 

I know I'm replying to an old thread but I just found this information and it answers my questions about that wire. It also explains the purpose of the single wire that I found on the side of the transmission. I will be removing that complete system as the motor will not be stock when it is reinstalled. My question is about the "light" that was mentioned in another explanation of this system, perhaps not on the C3 vettes. My instrument panel is currently removed from the car and I was wondering if there is a light on the dash that may need also need to be removed. The solenoid on the side of the carb will be retained and wired into the ignition and used as an "anti-diesel" solenoid.