Choke Wire 1406

[Grandpa Hilljack]

I recently bought this 80 C10 with a nightmare for wiring. I replaced the engine harness with one from a junkyard. I am using the dark blue wire to power the choke. However, this will not make it work. I ran a wire from the battery as a test to the choke and it started opening. So the choke is ok. The blue wire has 12v until I connect it to the choke. It comes straight from the power block.
What would cause this?

 

[AuroraGirl]

I recently bought this 80 C10 with a nightmare for wiring. I replaced the engine harness with one from a junkyard. I am using the dark blue wire to power the choke. However, this will not make it work. I ran a wire from the battery as a test to the choke and it started opening. So the choke is ok. The blue wire has 12v until I connect it to the choke. It comes straight from the power block.
What would cause this?

blue wire? My 1980 K25

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In my wiper spot I put a fuse tap in the correct direction(they are directional) and put a purple wire for no reason other than first to grab, and ran it through the firewall and put it on my choke.

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just because I was feeling thrifty I put the blue conduit around it and ran that most of the way back to just keep it from being too exposed, it may hold more in the future as things get changed.

The yellow to the alt bracket is my ground I decided to use. That ground path is fine since the battery is right next to it.

 

[Grandpa Hilljack]

Yes sir it’s blue. I think it ties into the oil pressure switch if I’m reading the diagram right. No guarantee there lol. I’m still trying to sort out what the last pink and pink/white wires are for. This harness came off of a later model. 84-85 I’m not 100% sure. I was just happy I found one intact in good shape.

 

[AuroraGirl]

Yes sir it’s blue. I think it ties into the oil pressure switch if I’m reading the diagram right. No guarantee there lol. I’m still trying to sort out what the last pink and pink/white wires are for. This harness came off of a later model. 84-85 I’m not 100% sure. I was just happy I found one intact in good shape.

these wires are unlikely to be enough current for your thing, and a pressure switch is a one wire deal unless its got 2 i think, but im pretty sure thats not a 12 volt source.. i could be wrong.

I would just do a fuse tap, find it at the auto store, and then run a new wire. you can use an used circuit or one that is key on

 

[Grandpa Hilljack]

I agree I think that’s going to be the easiest route. This poor thing has had a rough past life. I’m working on getting it back together, but the more I dig the more I find!

 

[Grandpa Hilljack]

Random primer all over the truck. No reason…. Just bored I guess. ‍

 

[ali_c20]

Some information on this

https://www.gmsquarebody.com/threads/electric-choke-power-source.10826/

Running a wire with an 20 amp fuse from any position that is hot when ignition is in run is surely the easiest fix.

 

[fast 99]

I agree I think that’s going to be the easiest route. This poor thing has had a rough past life. I’m working on getting it back together, but the more I dig the more I find!

The first picture shows the oil switch that provides power to the choke only when the engine is running. It is the smaller switch on the back of the block.

 

[Grandpa Hilljack]

I jus my have the sending unit. Should these have both the sender and the switch running off of a “T”? If I understand correctly, the switch turns on the choke light of you lose oil pressure. And leaves it on until over 10 psi at startup. I’m going to run a new wire from keyed power. I was just curious.

 

[RoryH19]

I recently connected my choke wire to the inside of the cab. It was easier to find an ignition hot wire next to the fuse block.
It's the red wire connected to pink. Reminds me I need to make it a little nicer.

 

[78C10BigTen]

blue wire? My 1980 K25

You must be registered for see images attach

In my wiper spot I put a fuse tap in the correct direction(they are directional) and put a purple wire for no reason other than first to grab, and ran it through the firewall and put it on my choke.

You must be registered for see images attach

just because I was feeling thrifty I put the blue conduit around it and ran that most of the way back to just keep it from being too exposed, it may hold more in the future as things get changed.

The yellow to the alt bracket is my ground I decided to use. That ground path is fine since the battery is right next to it.

I did the exact same thing with my truck except i didnt use a fuse tap.

 

[MikeB]

If voltage on the choke wire goes from 12 volts static (disconnected) to just a few volts or zero volts when connected to the choke positive terminal, that means all or most of the voltage is being dropped across some kind of resistance in series with the wire (or the source of the 12 volts).

The choke is simply giving the current a path to ground. With no path to ground, there's no current flow, so you will see 12 volts on the end of the disconnected wire. The wire should be 12 gauge minimum, but even 16 gauge would get you some kind of voltage at the choke connector -- probably around 6-8 volts depending on its length.

 

[Grandpa Hilljack]

Thanks all. I got it fixed. I just ran a different wire to it. Seems to be working fine.