Need help with mystery wire!

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foamypirate

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Hey guys,

As you know, I'm in the process of completing a TBI swap into my 84' C10. I'm running into a mystery wire in the old engine wiring harness that I'm not sure what it belongs to. I plan to tape it up and off to the side along with all the other wiring I'm not going to use, but it's just driving me nuts not knowing what it is. I can't find it on any wiring diagrams, and I can't seem to find it on the other side of the fuse block (though I could just be blind). I thought I had unplugged it from something, but going back through these original photos of the engine show it was unplugged when I got the truck...

The wire is green and ends in a brass terminal.

Things it's NOT (I personally disconnected these and have the wiring harnesses seperated from the truck):
TH350 lock up wire
AC compressor Signal
AC kickup solenoid signal
Water temperature sender wire


Any ideas guys? Here's where it's at:

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crazy4offroad

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Some had 2 temperature sender wires, one for the gauge and one for the ecm, one in each side of the block. And since it is green, and the terminal is probably the same kind as the one for the other sending unit wire, I say temperature-related.
 

foamypirate

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Some had 2 temperature sender wires, one for the gauge and one for the ecm, one in each side of the block. And since it is green, and the terminal is probably the same kind as the one for the other sending unit wire, I say temperature-related.

I had some similar thoughts, but this being a straight six, didn't have an ECM (no computer controlled timing).
 

Jims86

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Hey guys,

As you know, I'm in the process of completing a TBI swap into my 84' C10. I'm running into a mystery wire in the old engine wiring harness that I'm not sure what it belongs to. I plan to tape it up and off to the side along with all the other wiring I'm not going to use, but it's just driving me nuts not knowing what it is. I can't find it on any wiring diagrams, and I can't seem to find it on the other side of the fuse block (though I could just be blind). I thought I had unplugged it from something, but going back through these original photos of the engine show it was unplugged when I got the truck...

The wire is green and ends in a brass terminal.

Things it's NOT (I personally disconnected these and have the wiring harnesses seperated from the truck):
TH350 lock up wire
AC compressor Signal
AC kickup solenoid signal
Water temperature sender wire


Any ideas guys? Here's where it's at:

You must be registered for see images attach

May be for a cut off switch for the A/C at wide open throttle....look right above the eger valve in the pic. The reverse lights also used lt green, and green wires. Iw ill see if I have more diagrams.
 
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HotRodPC

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I see a dashpot or high idle solenoid on the old carb. I bet that wire goes there. I'll be back with an arrow.
 

HotRodPC

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That Wire !!!

attachment.php
 

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foamypirate

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That Wire !!!

attachment.php

See, that's what I thought too. But there was already a wire connected to that from the climate control harness (also green).
 

Jims86

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The only other thing i see so far, is the backup light switch, but thats at the bottom of the column...no?
May be time to have someone yank on them while you look for movement in the cab.
I have a stray green wire that I cut off of mine in that same spot.
It went to the Vac cruise control servo.
Looking in my Hanes manual, I found this. There is a temp switch of some kind other than the coolant sender that has a green wire.
You must be registered for see images attach
 
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foamypirate

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Crazy and Jim, you guys are right. I ended up finding it under the dash, and it ties into the same line as the water temp sender and goes to the cluster.
 

animal

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I vote that its a power wire for the flux capacitor
 

foamypirate

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I vote that its a power wire for the flux capacitor

That's funny...I just watched Back the Future the other day, and about to sit down with the wife to watch Back to the Future 2 literally in the next 30 seconds. :roflbow:
 

Jims86

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That's funny...I just watched Back the Future the other day, and about to sit down with the wife to watch Back to the Future 2 literally in the next 30 seconds. :roflbow:

Let us know what happens when you get it to 88mph.
 

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