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Discussion Starter #1
Help! Installed receptacle in side of pickup bed today (2004 GMC Sierra) but don't think I have the wiring correct. It's for a Fifth Wheel that I'll be picking up in a couple of weeks. There was a piece of tape on the end of the GMC harness with color codes, but it was not totally readable.

Here are the questions:

1. Receptacle has 7 connectors (6 flat and 1 round in center). Truck harness has 8 wires. Which wire is NOT used?

2. Which wire sends the signal to the trailer brakes? Red?

3. The brown wire is coded "RR LPS" Does that mean Rear Running Lamps?

4. Red wire is coded "PWR FEED". What does that mean? It's a heavy gauge wire.

5. Dark blue is coded "AUX". What is it for? It's a heavy gauge wire too. I'm guessing it just a hot lead which isn't used.

6. What is the light blue wire? Cant read the code on it. Looks something like "?? MTD STOP LP".

Man, I thought this would only take an hour to do....

Thanks,
 

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1. the wires you need are:


left turn=yellow
right turn=green
brown=park lamps
white=ground
blue=Electric Brakes
orange=power

Optional can't remeber green or lt. blue=backup lamps. I think the 8th one might be center high mounted stop lamp (maybe light blue). Not commonly used.


2. blue but only if you have a brake controller


3. not sure exact term but they are the park lights on seperate circuit for the trailer


4. Power wire to charge your camper battery.


5. Brake control wire same which is required in question #2


6. IIRC that will be the high mounted stop lamp.





Here is how you would normally hook this up. I assume you are using the 7 wire camper style plug with the flat terminals.


Truck -------- Camper 7 wire plug


yellow lt turn red
brown pk lamps green
green rt turn brown
white ground white
blue brakes blue
orange power black

Normally I would leave the center one empty but if your trailers have back up lights you could hook up the back up light wire to that terminal. The high mounted stop lamp (lt blue) is not used on automotive trailer applications.Edited by: Max Power
 

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Discussion Starter #4
Max Power,


You are THE MAN. You should consider working with vehicles for your living. Ooooops, forgot about your porn career: 12'' in limp mode. Oooops, forgot again: limp mode doesn't work well in porn.



Thank you!
 

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Discussion Starter #5
Sfischer,


Your link was excellent too and very helpful.


Bottom line is: use the stinkin' voltmeter and actually see which lead becomes "live" when each truck function is used. Stupid me for not thinking of this BEFORE cutting and stripping the wires. The harness is only about 3' long, and only barely reaches the hole I cut in front of the wheel well, and now I'm going to need to shave off another inch of wires to fix my first installation.


Thanks guys. You are the best.
 

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Thanks Max,


I'm just getting around to installing the bed mounted plug and asking myself those same color coding questions.


One thing, in a previous post you'd said something about not normally using the backup light wire. Both this truck and my '01 Cherokee came with factory installed trailer packages and both had the backup light wire hooked up on the center pole of the plug, so I figured I'd hook that up in the bed plug as well.


When I get ready to buy the "Toy Box" I may insist they install backup lights if it doesn't already have them....



I even put them in my horse trailer, once you've had them, spotting at night is so much easier.
 

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I just went through all of this last night. I was also confused with having eight wires for a seven wire plug. The light blue wire was the only one that I did not use (for a high mounted stop light). The piece of tape that the factory puts on the end of the wiring bundle was essentially worthless, since I could not read it. However, using a test light, I figured out what was what. My only question is, do you need to install the provided fuse in the fuse panel? The literature said that you did not if the truck has the auxiliary battery option. Since the DMax's have two batteries, I would assume that this is equivalent to an auxiliary battery for a gasser. Once I figure this out, my intall will be complete. Thanks.
 
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Where are yall putting the recepticle?
 

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Discussion Starter #9
Max,


One more thing. I'm refining your instructions into a Word document for personal future reference.


You indicate the truck ORANGE wire is the POWER connector. My harness does not have any orange wire, so I'm assuming the BRIGHT RED wire is the correct power connector, correct?


To summarize: here is what the connections should look like:


TRUCK FUNCTION POLLAK PLUG FIVER PLUG WIRE


yellow left turn #5 red


brown parking lamps #3 green


green dark right turn #6 brown


white ground #1 white


blue dark trailer brakes #2 blue


red power for battery #4 black


green light backup lamps center post yellow


blue light high mount stop no connector unused


Please correct me if any errors. I'll rewire and test with voltmeter later today and will repost if any are incorrect.


Note: Ignore the colors stamped onto the Pollak plug. They only confuse the installation since the truck wires you are plugging into these locations do NOT match what the plug indicates. Use the Pollak plug numbers stamped next to the colors instead. My eyes are so bad, I can hardly read what is stamped on the plug, so I have taped and numbered the terminals on the circumference of the plug instead.


Edited by: Rollin' Thunder
 

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Yes your right about the red. I was going completely off of memory. The older trucks is orange (88pre) and sometimes I get confused in my old age.






Boilermaker - leave that fuse out unless you are towing a camper and need the live wire in the plug. If that is the case, plug the fuse in.
 

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TEXMudder said:
Where are yall putting the recepticle?

Mine is in the ds inside panel behind the wheel well.
 

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If you putting it on for a camper don't forget to install the Fuse to charge the camper battery. Location of Fuse
 

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Boilermaker said:
I just went through all of this last night. I was also confused with having eight wires for a seven wire plug. The light blue wire was the only one that I did not use (for a high mounted stop light). The piece of tape that the factory puts on the end of the wiring bundle was essentially worthless, since I could not read it. However, using a test light, I figured out what was what. My only question is, do you need to install the provided fuse in the fuse panel? The literature said that you did not if the truck has the auxiliary battery option. Since the DMax's have two batteries, I would assume that this is equivalent to an auxiliary battery for a gasser. Once I figure this out, my intall will be complete. Thanks.

Boilermaker, I installed my trailer brakes and plug for my horse trailer yesterday on my 04 D/A, and noticed no + Batt coming to the stock plug on the hitch. I used the adapter cable for my Prodigy controller, also have the dual batt so I didnt put the fuse in that was provided with the controller adapter from the factory. How do I get + batt to the plug? Seems like I'm missing a fuse somewhere.


Thanks
 

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Aaaah, the search tool is a wonderful thing, too bad I didnt use it before my last post.
Seems I'm not the only one that was confused by the wording GM put on the brake controller harness regarding the fuse. Will put it in tonight, should have + at the plug then.
 
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