What is TCS switch for??

[76L82]

My 76 has a 4-speed and I am trying to figure out how to fix the mechanism that operates my reverse lights...which are stuck on in the reverse mode all the time.

My guess is that there is a switch off the reverse gear rod that is stuck in the activated postion. As time is so scarce...and the fact that it is 30 degrees and I hate to appraoch projects under the old beast without first having a plan...I am wondering if the TCS switch is the technical name for the mechanism that operates the reverse lights???

Thanx!

 

[BlackRat]

The TCS is for throttle control sensor. I really don't think that this is where your problem lies. I am converting my 71 from an auto to manual and have researched the wiring pretty diligently because I am going to remove all of the TCS crap anyway. It sounds like a bad switch at the trannie to me. Hope this helps.

Wade

 

[MMM]

I believe that TCS actually stands for "Transmission Controlled Spark". It allows the vacuum advance to operate depending upon what gear you are in. It is an early smog control device. I also seem to remember it was interlocked with the engine temperature sensor so that it would allow advance while the engine was warming up or if the engine got too hot. I need to look it up in my Chevrolet Service Manuals when I get home tonight to double check my memory. When I moved to California in the early 70's one of my cars needed a "smog" retrofit. The majority of these devices consisted of a thermatically controled vacuum switch that essentially shut off the vacuum advance unless the engine got too hot. The switch was installed into the upper radiator hose. The most interesting of these devices consisted of two rubber plugs (one for the vacuum source and the other for the vacuum advance cannister) and a warning sticker that stated that use of this device could cause the engine to overheat!

 

[BlackRat]

Ok so I was a little off in the acronym:duh Still should not cause the problem that you are seeing.

Wade

 

[MMM]

BlackRat is correct, the TCS switch will not cause your problem. I had a '75 L82, four speed convert, which should be mechanically similar to your '76. The backup light switch was mounted on the shift linkage (left side of trans) and had to be accessed from under the car. If I remember right, it was a tight squeeze getting to it because of the exhaust pipes.
One last point, I now seem to recall that the '75 did not have a TCS switch. I would be surprised if your '76 does. I believe the TCS was installed to control unburnt HC emissions. The addition of the cat converter in '75 reduced that emission to the point that TCS was no longer required. Ignition timing was still retarded over as compared to the pre-emission days, but the vacuum was not shut off at various times.

 

[76L82]

Thanks for the input!! As I am a horrible mechanic on vehicles before emissions controls...it gets a lot uglier for me after emissions!! I really struggle to see if this EC stuff really works on the mid-70's cars.. I have a sensor on the 76 Vette that runs from the top of the intake manifold by the thermostat housing and which I believe from memory connects to the EGR valve. I went to check it and it basically popped out in my hand. My manuals stated that without it the car would run rough, refuse to idle properly, yadda, yadda, yadda. I wanted to see what would happen, so I ran the car without it pugged in...absoluely nothing happened.

I have a 75 SBC in my 70 Camaro and it has nothing for emissions controls...what a breeeeeze to work on!!!