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Discussion Starter #1
I just got this truck and am trying to get the trailer lights to work. The plug seems to be in good shape however I traced the wiring harness along the frame and found the end under the cab not connected to anything. Help!
 

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Welcome to the club. Sorry I can't help with the wiring ( I hate wiring. LOL) but I'm sure someone on the site can.
 

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Give it some time and someone will have a answer. Alot of guys are at work this time of day.
 

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I just got this truck and am trying to get the trailer lights to work. The plug seems to be in good shape however I traced the wiring harness along the frame and found the end under the cab not connected to anything. Help!
Does the Wiring Harness look to be Factory or Aftermarket??......also if you can get a Picture of the Wiring that is not connected, that would really help as at this point it's going to be hard for any of the member's to said what and/or where those wires go that you have underneath the Cab??

Also you may check with the Dealership or who every you bought the Truck from to see if they know anything about......those wiring's not being connected under the Cab??.....I'm sorry but I at this point have no idea about those wire's not being Connected.
 

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Discussion Starter #6
The end of each wire has shrink tube on them as if they were original from the manufacturer and never connected. they were tire wrapped up under the cab.
 

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The end of each wire has shrink tube on them as if they were original from the manufacturer and never connected. they were tire wrapped up under the cab.
Ok got ya......I'm still at a lost as to where and what those wire's are supposed to go????.....I'm sorry.......:neutral:....Hang in there we have got some guys that are very good with wiring here on the Site....
 

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Discussion Starter #8
it a mystery to me too! Where should the trailer pigtail plun into? From everything i have read there is a plug above the spare tire that it should plug into. That plug is there on my truck but that wiring harness runs forward as well. It looks to me that someone tried to hook it up but gave up.
 

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it a mystery to me too! Where should the trailer pigtail plun into? From everything i have read there is a plug above the spare tire that it should plug into. That plug is there on my truck but that wiring harness runs forward as well. It looks to me that someone tried to hook it up but gave up.
I'm......with you on the Wiring plugging in next to the Spare.....that is your Taillights .......This may be a dumb question.....have you tired hooking up a (trailer) and then Plugging the wiring from the Trailer into the wiring harness on the Truck.......to see if you have got power to the lights on the Trailer.....I'm just guessing at this point....:glasses:
 

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The wires going up under the cab, is it just 2 wires? Perhaps an orange and a blue wire? If so, that's for your electric trailer brakes. The orange wire would hook up to one of the aux busses in the under-hood fusebox and the blue would hook up to the trailer brake controller output. All the trailer lights should hook up at that junction box by the spare tire.
 

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The wires going up under the cab, is it just 2 wires? Perhaps an orange and a blue wire? If so, that's for your electric trailer brakes. The orange wire would hook up to one of the aux busses in the under-hood fusebox and the blue would hook up to the trailer brake controller output. All the trailer lights should hook up at that junction box by the spare tire.
Thanks Chris.....Wiring is not a item that I know all that well....:glasses:
 

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Let me also mention that what I describe previously only applies if the person installing the wiring does it as GM intended... I've seen trucks that the installer spliced into all the wiring under the bed when simply plugging in 1 connector does the job perfectly...
 

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Discussion Starter #13
the pigtail that runs under the truck from the trailer plug has all of the wires for a 7 pin connection but no plug on the end, It just stops under the cab. The plug over the spare tire is plugged into a pigtail but it runs back up front.
 

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Did the truck previously have a camper top or 5th wheel hitch in it? It confuses me why the wiring would head back to the front of the truck like that.
 
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