trailer wiring 99 suburban

I have a 1999 Suburban that I am trying to wire a 7 pin RV plug on.

My question is about installing a brake controller and auxillary power.

The owners manual says that there is a "Light-Duty Wiring Harness" & an "Additional Heavy-Duty Wiring" harness. The light duty harness is supposed to be a 5-pin harness which I do have. The Heavy Duty harness is supposed to be 8 wires and is not supposed to have a plug from the factory, which there doesn't seem to be.

The manual breaks down what color wire is supposed to go to what. There should be a blue wire, which is to go to "Auxiliary/Electric Trailer Brake Circuit" and an Orange wire, which is for a "Fused Auxiliary Circuit". I found a heavy guage Orange wire and a heavy gauge blue wire, both are loose, but appear to be part of what I would guess is the 8 pin wiring. I can't get power to either of these, should there be? ....or is there a fuse that needs to be installed? I suppose that the blue wire goes under the dash somewhere, so that a brake controller can be connected, but I couldn't find anything on this.

Anyone know where to begin? I have everything else working I just need these two wires.

Thanks

Reply to
MASTER Brian
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Not sure exactly what you're asking, are you looking at the wires from the plug end or the front end. First thing see where they go, they may not be hooked up to anything. On my truck they just left the two wires sitting in the engine compartment. This could have been done by a previous owner as well.

The blue wire should go to the output of your brake controller. Other wires needed for brake controller are power, ground, and signal from your brakes. The best bet on the aux power wire is if it isn't already hooked up, just run straight to the battery and fuse it. Keep in mind all this wire does is run 12v for either charging a trailer battery or running onboard accessories, so depending on what you're towing you may not even need it.

MASTER Brian wrote:

Reply to
89GMC

I need both ends. The manual says there should be a wire for a brake controller and aux power. One blue, one orange. I believe I have them on the plug end, just need to know where to look on the front end. I have done some searching on google as well and you might be correct, the wires may just be "dead" on both ends and not hooked to anything, but I need to find them. I'll try the fuse block as well as around the brake booster. I would think the brake wire would be under the dash as well, since that's where a brake controller goes.

Sure would be nice, not having to run new wires.

At this point, I probably don't need the 12v wire, but I figure might as well hook it up while I'm here if it's there without much work. Who knows when it will come in handy. I do have a box camper I tow, but my understanding is the chargeing system on a car will mess up a deep cycle marine battery, which is what I use in the camper, so I don't need it for that.

Reply to
MASTER Brian

No easy answer on where to look for them up front, I actually could see where mine ran up the framerail from the rear in a loom and crawled under the truck and followed them up to where they went under the hood. If you do find ones you think are them, you could always make a jumper to run back to the plug end and do a continuity test to make sure you're right.

MASTER Brian wrote:

Reply to
89GMC

That's what I was hoping I could do! Thanks!

Reply to
MASTER Brian

Do you know anyone that pulls phone or computer network cable for a living? They have a tool called a toner that sends a signal down a wire, the receiver is just run over the outside of wires till it starts emitting a tone(hence the name toner). Its a very handy thing, imagine the server room, 150 cat 5e cables, all blue and none of them labeled, which one goes where?

Whitelightning

Reply to
Whitelightning

Actually, my cousin does this work, maybe he has one. Only problem is he is

90 minutes away! I'll keep that in mind though.

I think I may have actually found the "other" end of my wires. There is are two wires just under the booster cylinder that match the wires at the hitch. They aren't hooked to anything, just boundled up. The orange wire, which the book states is a 12v wire, has a ring terminal on it and reaches perfectly to the fuse block, where a 30 amp fuse and terminal are. The blue wire, which is the accessory/brake controller wire is longer and the perfect length to reach under the dash.

Unless I can locate a toner, nearby, I may just ground both wires out and see if I get a reading. Neither end reads hot or ground.

Thanks for the help!! It's nice that the auto companies plan ahead a bit now days!!

Reply to
MASTER Brian

Brian,

That's exactly where I found my wires. If you have a multimeter and some spare wire, here's an easier way to test..... cut a piece of wire the length of the truck. Hook one end to whichever wire you're testing at the plug. Drag the other end up front with you. Hook it to one side of multimeter. Now if your meter has continuity use that, and touch the other probe of meter to the wire you think it is, it should beep. If you don't have continuity on your meter, do the same thing but use the resistance measuring feature, you should get very very close to 0 if you have the right wire. Repeat for other wire.

MASTER Brian wrote:

Reply to
89GMC

I tested and those are the correct wires! Very nice!!

Thanks for the help!

Reply to
MASTER Brian

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