Chevy headlight wiring

rich p · Apr 19, 2007

I am trying to wire the headlights on an 81 chevy 1 ton pickup. The headlights have the standard 3 prong sockets. I think it is one prong for low beam, one for high beam and one for ground? Not sure which is which. I have to splice them back together as someone butchered the factory harness for plow light hook up years ago.

LD · Apr 19, 2007

Is this a question?

Pull the lights on dim. Use a voltmeter. clip the black lead to the chassis; touch the red lead to one of the wires. 12v...that's the dim.

Hit the high beam; touch the red lead to the other 2 wires... 12v, that's the high. Ground to ground will be zero.

Don't have a meter? Pull the lights on dim. Carefully and quickly scratch a wire across the chassis. Sparks = dim. hit the high and scratch with the other 2 wires. sparks = high. NO spark = ground.

rich p · Apr 19, 2007

I guess my question is, which prong goes where.

Mike Folks · Apr 19, 2007

A website called Susquehanna Motorsports at www.rallylights.com may be what you are looking for. They list relays,horn and driving light diagrams and how to upgrade your headlamp wiring.

Do you have access to a meter to read voltages and resistance? It will be required along with someone to operate the switches in the vehicle

winchman · Apr 19, 2007

I think the real question is: Which prong on the bulb is hi beam, which is low beam, and which is ground?

Roger

Bill Simmons · Apr 19, 2007

I just went out and looked under the hood (it was already open so not much effort) of my 1970 C40 bucket truck. Looking at the back of the socket (ie, looking at the wires) the left most pin is ground, the center/high pin is low beam and the right most is high beam. The colors on mine are tan for low beam, light green for ground and dark green for high. I confirmed this using my $2.95 digital voltmeter that I just picked up from Horror freight this afternoon.

matt_isserstedt · Apr 20, 2007

I would urge using heat-shrink butt splices to repair the wiring harness, and pack the 3-prong socket with dielectric grease.

Anything less will last a few years and then leave you in the dark again.

Cog-Noggin' · Apr 20, 2007

Strip wires, twist together, solder, dielectric grease, then heat shrink with one size to fit over joint and another piece longer over that. Maybe a little overkill, but will outlast the truck.

matt_isserstedt · Apr 20, 2007

Nice thought, Cog, I guess what I was trying to say was...there will be enough other "repairs" with a truck of that age to keep you busy...and so you might as well knock out as many failure modes as you can while working on a specific system.

As I've posted before, I'd rather crawl around on the driveway for days at a time under the truck and spend money putting parts in/on it than spend a single hours on the side of the road with a flashlight doing the same thing.

rich p · Apr 20, 2007

Thanks Bill, that's what I needed.

Cog-Noggin' · Apr 20, 2007

I have been there Matt. One time I replaced the input shaft in a Jeep tranny on the side of the road in 3-1/2 hours. That was from start to finish, except for the front driveshaft. No ramps, jack stands, etc. Used the winch for a vice and three screwdrivers for snap ring pliers to replace the bearing. Had a small Craftsman toolbox but it was set up for anything.

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Chevy headlight wiring

rich p

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LD

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rich p

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Mike Folks

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winchman

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Bill Simmons

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matt_isserstedt

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Cog-Noggin'

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matt_isserstedt

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rich p

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Cog-Noggin'

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