84 wiring harness

[Matt_50]

I hope you guys can help me out. I have an 84 c10 auto, long bed. I've driven it a few years and I'm now stripping it for parts to get my 50 3100 running. I yanked out the wiring harness. And I had a lot of connections that went nowhere. I also had a couple of rectangular boxes under dash. I had a mechanic fix my distributor issues when I first got it. Couldn't figure out why it kept shorting out. He found a small bundle of wires, snipped, wrapped in tape and soaked in old oil. He said this year has a very basic computer... He did away with the small shorting harness and told me he put in a older style distributor.

Am I making sense? I want to strip out all unnecessary wires. I just want what I need to start it, have lights and a few interior goodies. Gauges, radio, interior lights, heater, wipers..

At the very least. Can you guys point me in the direction of downloadable wiring diagrams?

[Joe Z]

You're sort of making sense. I just went through a ton of electrical work on my 81' when I dropped a 66' motor in. A little more info would help. But let me get this straight, you are putting a 84 motor and trans in a 1950 3100 series truck? And the wiring harnesses has been "hacked up" prior to the swap? Does the motor have a tbi?

This link should have all the diagrams you need for and 84'

http://forum.73-87chevytrucks.com/sm...?topic=11766.0

[Matt_50]

All computer like stuff is gone. Carburetor with electric choke.

[Joe Z]

Did the original harness have computers?

[Joe Z]

Also are you using the the 84' column?

[Matt_50]

I was told by a mechanic a few years ago that it had had a very early one. Someone cut it out..literally. the wires were behind engine getting soaked in oil and kept shorting out distributor. Mechanic took out extra wires. There is no splicing, a lot of hanging connector though. Figured I'd just take off extra stuff.

[Matt_50]

I took it out...just in case but I'd rather use a 50s column. Keep the look you know. I thought I could trace wires and wire to the 55 neutral safety and stuff.

[Joe Z]

Ok, these harnesses are very simple and typically they are all the same with only the accessories being different based on options. If you are using the factory firewall connection you can plug in the factory harness from one side to the other and just change out the light connections for turn signals and headlights and if you use the 84' column everything will function exactly as it did in the old truck without too much modification.

The only wires needed to start and run the truck should be as follows:
Purple: starter wire for the ignition.
Red: goes from alt. to the ignition plug for wire 1 and wire 2 goes back to the battery if I remember correctly with the primary wire.
One wire should be ran from the carb and the distributor to a I believe an orange wire if I remember correctly but I'd double check that. (I like to add a relay to that so they get primary battery power)

Let me know if this is making sense. I don't know off had the wire colors for the lighting.

[Joe Z]

You can run the 84' column harness in the 50 column if you are skilled. It be good to use the 84' column plug at least so you can just unplug it if ever needed.

[Matt_50]

Thank you. Just the help I was looking for. I'll string the wiring out and take off all uneeded stuff. Ill use the diagrams to run wires again. And i might ask for your advice when hooking up.

[Matt_50]

I see what you mean...take off 84 plug on 84 column and wire all the 55 stuff into the plug then plug it in... right?

Then run the ignition switch stuff over to the dash switch.

[Matt_50]

That seems so simple now! Thanks alot for the idea. Why buy and make new connections for safety switch and turn signals.... Just wire all the column stuff to accept the plug for the harness.

I'll look at wiring diagrams and match up.

[Joe Z]

Feel free to ask. I know a guy who rewired a 55' sedan column I can see if he has any advice and get back to you. It should be simple enough to do though. I'd try to use the 84' firewall plug if you can so that you'll be able to use most of the original harness and have all the factory fuses. It should be easy to mount in the firewall discreetly to keep a clean factory look.

[Matt_50]

Originally Posted by Joe Z

Feel free to ask. I know a guy who rewired a 55' sedan column I can see if he has any advice and get back to you. It should be simple enough to do though. I'd try to use the 84' firewall plug if you can so that you'll be able to use most of the original harness and have all the factory fuses. It should be easy to mount in the firewall discreetly to keep a clean factory look.

I think I'll mount it like the c10. Be able to unplug sections if needed. I got one big empty connector, I'm guessing early computer maybe.. Also found a like black box I think was for the cruise control. I think once I clear all these out it'll look real clean.

Now I'm wondering about the gauges.. I guess that connection will need to go for individual ones huh. Since it plugs into a cluster instead of a separate connection.

[Matt_50]

Ask your buddy what he thinks.. And thank you for the advice.

[Joe Z]

No problem and I will probably see him tomorrow. As for the gauges everything is color coded on the harness plug so what ever gauges you decide on just cut off the connector for the back of the cluster and you could wire into the harness trouble free. I like to use plugs from s10's. They have multi pin (I think 7 pin) round plugs under the hood that are perfect for this type of work and make it easy to connect and disconnect the gauges as needed. I get them for less than $5 at my local pick a part. Or amazon has a lot of different connectors offers in many different options. Really though it's just about what's easiest for access ability but it ultimately depends on the gauges and there layout.

[Matt_50]

Using the column plug ....i could have turn signals, safety, and what..horn all go into the connector right? I suppose I could also run wires from the ignition switch into it too huh? The harness will plug in as if plugging into the 84 harness.

[Joe Z]

Yes, though I thought the 50's had the ignition and horn on the dash if not mistaken and the 49' I owned had a floor button pedal for the starter but I don't know what year that was changed over to standard ignition. if that was the case with yours the ignition cylinder wouldn't have the function for cranking the motor. It would only have a on/off switch allowing the truck to start and require a separate start switch. What setup does your truck have?

[Joe Z]

I talked to my friend and he said he used a digital prob to check and trace the original wires and replaced them but he said if you disassembled the top of the column (steering wheel, turn signal selector) you can use a string to tie around the wires and pull them out then tie the new wires to the string and pull it back through.