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What Is That Harness For?

grosss

By grosss
in Ask A GM Technician

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grosss Enthusiast

grosss

Posted
Posted

Here's something that's been bugging me for a while, there's a wiring harness/panel under the dash of my 93 silverado, it has a bunch of wide and flat pins to plug wires into (and one or two wires on it) and the relay for my turn signals, and 2 other relays. What are all of the pins for? what is the purpose of this panel? I found a lot of 12v supplies on it, so I tried wiring some stuff into it instead of having to run wires from the enigne bay, and whenever I turn on my headlights or even just the running lights the power to this panel gets cut.

 

At first I thought it was the trailering harness... but it would still need power if the headlights were on, then I thought it was for a snow plow, but.. same problem. Any ideas? Any idea how I can stop it from shutting off with the headlights so I can keep power constantly from it?

bobcat5544 Enthusiast

bobcat5544

Posted
Posted

From what you have stated it sounds and acts like it is the connector to day time running lamps. GM intergated that harness in so if the truck got sold in Canada that option could be put on since it was a requirment in Canada.

 

But to be sure I need to know what colors the wires are, how many slots there are in the plug and the exact location of the plug.

 

and a pic would help

grosss Enthusiast

grosss

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Yea I keep meaning to get a picture, I just left my camera at my girlfriend's house on the weekend and keep forgetting to grab it ;-). The strange thing about it though is it shuts off power when the parking lights are turned on (when i hit the top switch without hitting the bottom ones for the headlights) but the DRL's are still on at that point I believe since the headlights aren't on... I'll get a pic soon I swear!!

grosss Enthusiast

grosss

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Alright, picked up the camera, here's the best shot I could get of it

 

post-45959-1201152044_thumb.jpg

 

 

So ignore the white wire, that's the one I wired in myself, but one of the relays on the bottom says it's for the turn signals, and the other one just says "4RD" and I think there's a fuse in the fuse panel that says 4RD too... I have no idea what that is though. Thoughts on what this panel is and how I can power it all the time?

post-45959-1201152044_thumb.jpg

post-45959-1201152044_thumb.jpg

post-45959-1201152044_thumb.jpg

bobcat5544 Enthusiast

bobcat5544

Posted
Posted

That panel is just a power distubution center for lights, horns, and a few other things. The open pins are for curtain accesories for that truck. Like day time running lights, snow plows, trailer lights, and more..GM has after market wire harnesses that plug in if you are putting extra equiment on your truck...

 

Let me know what you are tring to hook up and do you want it to come on at a curtian time or are you going to control it with a seperate switch

grosss Enthusiast

grosss

Posted
  • Author
Posted
That panel is just a power distubution center for lights, horns, and a few other things. The open pins are for curtain accesories for that truck. Like day time running lights, snow plows, trailer lights, and more..GM has after market wire harnesses that plug in if you are putting extra equiment on your truck...

 

Let me know what you are tring to hook up and do you want it to come on at a curtian time or are you going to control it with a seperate switch

 

Hmm... ok, then why do all of the 12v lines in it shut off when you turn on the lights? Don't snow plows/trailer harnesses need power at night too?

 

Originally I was trying to hook up a low powered amp throught it, but I've since realized that there's not enough current from that source, so I'm going to have to drill a hole in the firewall and hook up a kit I bought for the amp to the battery, but now what I'd like to hook up to the panel is my XM radio, right now it's plugged into the cig lighter and the cig lighter always has power, so my XM doesn't shut off when I turn off the truck. I also want to route the power to under the dash so that I can clean up the wires in the cab, I did it in my car and it's a nice clean install :-).

 

But obviously if I can't figure out how to get the panel to stay on when the lights are on, i'll have to power it from somewhere else.

 

Oh and before someone points it out, yes I would put an inline fuse for the XM since it's not going thru the fused cig lighter anymore.

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