I now installed a plug in the back corner of my truck to plug my 5th wheel into so i dont have to plug under the bumber:help: and am trying to figure out how to hook up the wires. The plug i installed has 7 wires. Black-brown-red-blue-large white-yellow and green. The truck has large black-large blue-yellow-green-lt green-large red. If i plug the trailer into the factory plug on the truck everything works. Can any of you help me with the wiring this new plug onto the existing wires of the truck? The truck is a 2005 chevy 2500 HD

Thank you
Howie

The truck colors don't look right. Where are you getting those colors?

If you have a towing package there is a bundle of wires at the front of the box.

I do have a towing package. Are you saying at the front of the bed of the truck behind the cab?

Yes in front of the bed behind the cab on the drivers side outside of the frame there is a bundle of wire.

Bingo...should be rolled up and tucked between the box-n-cab. On the bundle tape, there is a label indicating what wire is what. Un-coil it & see how far it goes back to see where to drill the hole for your recepticle. I added an extension to mine so that it would reach to within 8" of the rear of the bed---did not want the trailer umbilical to interfere with the hitch plate, especially when turning----not to mention, its a heck of a lot easier to hook-up the further back you place the plug.

I see the bundle of wire and if i trace it back it goes the the front of the truck to the fuse block i am assuming and the other end goes into the factory hitch plug on the bumper.The guy i had install my other plug in the bed attached to those wires but the colors are not the same as on my 2002 so that is where i am confused.

What colors do you have there?

Should be:
Large blue
large white
green
yellow
brown
orange or red?
light blue?
light green?

It has the following:

Large Red
Large Blue
Large Black
Green
Light Green
Brown
Yellow

Stange. The large black is throwing me off. Are you sure? Do you have a digital camera to take a pic so I can make sure you have the right harness. I am going from memory but that doesn't sound right.

If you are certain those are right then it would be like this:

truck - plug
red - black
blue - blue
black - white
green - brown
light green - center wire
brown - green
yellow - red

That is providing you have a 7 wire rv style plug.

Good luck.

OK! I tried that set up and everything works except the left blinkers and brake lights. I did have one wire left over on the new plug which was a yellow so i still have something wrong.

The yellow should go to the terminal marked red which is the left turn signal.

I got everything to work now and did not need the yellow wire on the plug. This is the only wire left. I am assuming it could be for the back up lights? I tied the black into the red on the truck which said it was battery power so i am assuming that is what charges your batteries while you are driving correct?

Black on the plug, red on the truck? If so that is correct.

The yellow wire is for left turn. No two ways about it. If you aren't using that yellow wire there is something wrong.

What do you have going to the terminal marked 'red'? It should be a yellow wire.

IF you want the plug in the back of the bed you DO NOT have to add extentions to it!

The wiring bundle STARTS at the back of the bed near the hitch.. Just un snap it from the holders and pull it back to where yu need it... I just did mine and cut off 5 feet of extra wire...

Steve

GM on some of the newer models has been using black for a ground. Red should be your 12 volt feed which goes to the black terminal. Yellow goes to red like Max said. Brown goes to the green terminal. green goes to the brown terminal and blue to the blue terminal. Black to the white terminal.

Thank you all for your help. Now the yellow wire that i had left was from the plug. I did use the yellow wire from the truck and tied that into the red wire from the new plug i installed. Everything works so either i got lucky or something on the new trucks are different. Does this sound correct?

Howie

if you will read the manual it tells you exactly what color goes to what function. then just match the new plug to the old. plug that came on truck has wiring position on the plug flip up cover.:)

Gm has changed the color of the ground in there wire harness on some 05's
Gm code
Black= Ground
Red = Hot feed
Yellow = L Turn
D Green = R turn
L Green = back up
Blue = Brake
Brown = Tail

Trailer code
Black = Hot Feed
White = Ground
Red = L Turn
Green = Tail
Brown = R turn
Blue = brake
Yellow = Back up

I am getting ready to switch from a TT to 5th wheel and I don't think I have the 5th wheel wiring. I have looked all around between the bed & cab. I can't believe it because mine came with the extending mirrors and everything. But anyways that factory harness is like $75. Is it worth it or should I just tap off the factory wires and make my own harness? Or does anyone know of aftermarket harness that do the same thing that are cheaper?

I would personally tap into the wiring, but I do tons of these things.

Look for the wiring between the cab and the box on the outside of the frame on the drivers frame rail. It will be bundled up just in front of the front box mount.

How does the factory 5th wheel harness connect? Is it almost like a T connector. Do I just connect it between my current plug and wiring harness?

It plugs into the rear junction block where the taillights etc plug in and runs forward.

I just found a cable at www.etrailer.com that sounds like it is the same thing as the factory 5th wheel harness and it is only like $33. It says it plugs into the factory harness and is for a 5th wheel connection in the bed. Hopefully it is what I am looking for without spending $75.

I got that harness today. It is the same thing as the factory harness that costs $75+. It doesn't have the nice factory frame rail clips and plastic looming but it plugs into the factory plugs just like the factory harness. It is wrapped in that black fabric tape, like gaffers tape. For half the price I though it was a good alternative.

I would love the part number from etrailer.com for that harness. I looked at their website but didn't see that part.

The Yellow Is For Your Backup Lights On Trailer. Black = Hot White = Ground, Green=running/tail Lights Red = Left Sig. Brown = Right Turn. The Red And Brown Also Light Your Brake Lights.

The Yellow Is For Your Backup Lights On Trailer. Black = Hot White = Ground, Green=running/tail Lights Red = Left Sig. Brown = Right Turn. The Red And Brown Also Light Your Brake Lights.:confused: GM has a standard on the wiring it is Black/White= Ground, Green = Right turn, Yellow= Left Turn, Blue= Electric Brakes, Red/Orange= 12 Volt Power, Brown= Taillights, Lt. Green= Reverse Lights.

I Just Plug Mine Into The Standard Plug On The Bumper. Works The Same !

Arm