Wiring experts,

Working on wife's 72 SS (actually re-doing entire car!) On the engine harness, there is a brown wire w.a straight, single blade push-on connector that comes out of the harness right near the engine temp. sending unit wire. I have no clue what it is for as it was just laying along the intake manifold when I took the engine out. It also had been cut and then spliced with one of those blue, fold-over repair things (not impressive at all!) Can't really decipher what it's for according to the wiring diagram, either. Help me out guys, so I can clean up and re-wrap this harness!
TIA for your assitance.

A/C magnetic clutch I believe.

Their is also a brown wire that goes to the coil that is used if you have a Tachometer. It is listed as circuit 121 in the 72 service manual.

Thanks to both ofyou guys for the info. This car has neither tach or AC. I will just repair it and put it back where it was. I might even fold it under the harness so it doesn't look out of place along the intake manifold. Thanks again! I normally can be found over at Team Chevelle as DUKE 69 but I registered here as I did, because the car belongs to my wife. Pressure is on to get it finished before fall....maybe

It may be for the idle stop solenoid that was energized with the key on and was the adjusting point for the base idle. When the power was removed the solenoid retracted lowering the throttle arm and completely closing off the throttle plates. This helped prevent dieseling. There was also a TCS circuit it may have powered. The systems are both outlined in the service manual section 6T.

BTW I do have a spare 72 GM factory service manual in like new condition I might be willing to sell :) You can also buy them new from the original printer Helm Manuals (http://www.helminc.com) for $60.

BTW I do have a spare 72 GM factory service manual in like new condition I might be willing to sell :) You can also buy them new from the original printer Helm Manuals (http://www.helminc.com) for $60.

What would a person do without the origional grease outs and oil highlights of an origional manual that was actually used in a shop! :D I got my grandfathers from then he worked on GM vehicles for 35 years. He has some good little side bar notes written here and there!

Phil,

Thanks for the offer, but I have the service manual, as well as some for the same yr. Chevelle. The idle solenoid makes sense and the fact that this is a Calif. car makes it seems even more likely. It was just laying there along the top edge of the left side valve cover and covered w. gunk. The current carb does NOT have the idle solenoid on it ( I remember those things!) Also, I should have been a little more "color-specific"... the wire is TAN, not brown but that still makes your idea quite plausible. Just trying to get it a little more "correct" than it was and wiring is not my favorite part of car restoration. Thanks!

Factory wiring harness were based upon trim level as I recall with every thing that could be optioned wired into the harness and ready to go. It was cheaper to have a few extra wires than it was to have a custom woven loom for every car. Even thought they would scream bloody murder at having an excess three inches of wire per car so that any given harness barely reaches every part of the car. Definitely could use an assembly manual for all my rides but I have gotten by with the service manual and the wiring manual and the occasional body by Fisher book showing the interior parts and trim that I have only one of.


Big Dave

Glad you have the manual. One thing I do not understand about this hobby is how someone would spend $10K + to build their ultimate dream hot rod and be to cheap to buy a manual. Of course I am kinda obsessive about manuals I just ordered a 3 book set for the 77 Nova from Helm and I really do not need it, I think the 75 one would be pretty much the same. It is time to build another book shelf in the garage and according to Helm I have 7 - 10 working days.

I know what you mean when it comes to manuals. I like to have them around myself. In fact, I "inherited" literally a pickup truck load of them from the local GM dealer when they were cleaning out. They had bought out some other dealerships so there were many duplicate books. My friend,who happened to be the parts manager at that time, told me to get there quick or they were history. I went! Most are later-model stuff, some bus and large truck stuff but hey, don't throw that stuff away...yet.