71 c10 Wiring harness help - what is this?

[Mingrao]

I do not think that this was connected to anything when I took the truck apart. I labeled everything and these wires were not labeled, but I have made mistakes before.

Can anyone tell me what these wires go to?

This bundle of wires comes off of where it is bolted to the fire wall. About 4 feet of wires.

[Mingrao]

Driver side fire wall

[Mingrao]

One of three connectors

[Mingrao]

2 of 3

[Mingrao]

3 of 3

[Livrat]

its part of the TCS control system, if your not doing a concourse restoration just remove it all and toss it

[Mingrao]

Livrat, thank you so much. I didn't think it was important. Can you tell me a little about the TCS? I did a quick google search on it and there was not much out there on it. Did the wires connect to the transmission? I have a period correct 3 speed manual in it as it was vrom the factory and there is nothing on the trans to hook this stuff up to.

Thanks again!

[Andy4639]

Picture three is your brake warning wire for the master cylinder proportioning valve.

[Livrat]

Originally Posted by Mingrao

Livrat, thank you so much. I didn't think it was important. Can you tell me a little about the TCS? I did a quick google search on it and there was not much out there on it. Did the wires connect to the transmission? I have a period correct 3 speed manual in it as it was vrom the factory and there is nothing on the trans to hook this stuff up to.

Thanks again!

Sorry to say I do not know much about how it works but did find this
http://www.73spot.com/index_stats_fi...ission/tcs.htm

Originally Posted by Andy4639

Picture three is your brake warning wire for the master cylinder proportioning valve.

Andy, I am not sure that's where it goes, I do believe the brake warning light wire is brown, to my eyes that one looks to be black, but I could be wrong.

[darush01]

I don't think that's the wire from the proportioning valve mine is brown as previously mentioned and the plug is a little bigger

[Andy4639]

Maybe, but don't go by color alone. That doesn't mean a lot on a truck 40 years old and has had multi owners doing wiring on it.

[Mingrao]

Originally Posted by Andy4639

Picture three is your brake warning wire for the master cylinder proportioning valve.

Thank you Andy4639!

[SS Tim]

In 71 it was known as the C.E.C. (combined emission control system). If you want to know more about it and how it works look it up in the 71 factory service manual (section 6Y) and also the 72 manual for better description and trouble shooting.
As far as not finding much info, try using the forum/site search box, I've posted a couple of TCS replies in the past week.
The connector in picture 3 is most likely the trans. switch connector but I am fuzzy as its been a long time since I've had to work on a live CEC/TCS system.
The brake switch wire in every factory application I can think of was a tan wire as pictured below that dropped out of a cut in the wire gutter over the M/C and booster then down to the combination valve.
As far as CEC/TCS not being needed, its not and can be worked around. Just remember it was part of a system so make sure you understand and address anything it controlled along with engine adjustments because of it.
If you don't have a factory service manual get one or at least download a workable copy to reference.
* VIN/Model Decoders
* Power Team Charts (engine/transmission/gear ratio)
* Post Your Pickup SPID Blazer SPID Suburban/Panel SPID
* RTFM ... Read The Factory Manuals... download 'em here

[SS Tim]

Trans. switch.