2009 Trailer Wiring

[jwichman]

I have a 2009 silverado 2500hd. Under the hood near the fuse box I've found 3 red wires 1 for trailer brakes, 1 unmarked that I've traced to the trailer plug on the rear bumper for 12volt aux power to the trailer and 1 that is marked 12volt aux trailer power feed. Does anyone know where the wire marked 12volt aux trailer power feed runs? I'm the original owner of the truck so I know there haven't been any after market modifications done. Any ideas why 2 aux power trailer feeds and where the second one runs?
Thanks

[GMCustomerService]

Originally Posted by jwichman

I have a 2009 silverado 2500hd. Under the hood near the fuse box I've found 3 red wires 1 for trailer brakes, 1 unmarked that I've traced to the trailer plug on the rear bumper for 12volt aux power to the trailer and 1 that is marked 12volt aux trailer power feed. Does anyone know where the wire marked 12volt aux trailer power feed runs? I'm the original owner of the truck so I know there haven't been any after market modifications done. Any ideas why 2 aux power trailer feeds and where the second one runs?
Thanks

jwichman,

If you were able to provide us with the last 8 digits of your VIN, we could consult with an internal technical resource to see if they would be able to provide any insight. Please send it to us via private message.

Sarah (Assisting Erica)
GM Customer Care

[j cAT]

Originally Posted by jwichman

I have a 2009 silverado 2500hd. Under the hood near the fuse box I've found 3 red wires 1 for trailer brakes, 1 unmarked that I've traced to the trailer plug on the rear bumper for 12volt aux power to the trailer and 1 that is marked 12volt aux trailer power feed. Does anyone know where the wire marked 12volt aux trailer power feed runs? I'm the original owner of the truck so I know there haven't been any after market modifications done. Any ideas why 2 aux power trailer feeds and where the second one runs?
Thanks

what are you trying to do with these connections/feeds ?

I would go to alldata and get the wiring diagrams to help you do whatever your trying to do !

you could go to the dealership and see if they have a person to help you .

[MT-2500]

Originally Posted by jwichman

I have a 2009 silverado 2500hd. Under the hood near the fuse box I've found 3 red wires 1 for trailer brakes, 1 unmarked that I've traced to the trailer plug on the rear bumper for 12volt aux power to the trailer and 1 that is marked 12volt aux trailer power feed. Does anyone know where the wire marked 12volt aux trailer power feed runs? I'm the original owner of the truck so I know there haven't been any after market modifications done. Any ideas why 2 aux power trailer feeds and where the second one runs?
Thanks

One for rear trailer plug and one for 5 wheel trailer plug on left side of truck.
As said tell us what you are trying t do ad get a good wiring diagram.

[jwichman]

Originally Posted by MT-2500

One for rear trailer plug and one for 5 wheel trailer plug on left side of truck.
As said tell us what you are trying t do ad get a good wiring diagram.

I have a slide in pickup camper and pull a horse trailer at the same time. The horse trailer has electric brakes & 12V aux power, the camper needs aux 12V power. I have the brake lead hooked up to the brake post (under hood fuse box) and one of the 12V power feeds hooked up to the 12V aux power feed post (at the under hood fuse box) all works well, just wondering what the third wire labeled "Aux Trailer Power Feed" is.

Just this morning I discovered an issue. It seems that the camper refrigerator (3way powered - LP gas, 120V AC or 12V DC) wants it's own dedicated 12V power feed. It appears that when the camper is plugged into the truck the electric brake feed is wired to the 12V DC refer power. So now I'm looking for an additional 12V AUX power feed for the camper. When I find it I'm not sure how I'm going to get it there as I'm already using all 7 wires of my 7 pin trailer plugs....any thoughts or ideas? I am currently using the rear 7 pin recepticle with a Y adapter I found online to plug both the trailer and the camper in at the same time.

If there is another 5th wheel trailer lead on the left side of the truck this would solve my issue; can you tell me where I can find the wire?
Thanks,
John
Thanks,

[j cAT]

Originally Posted by jwichman

I have a slide in pickup camper and pull a horse trailer at the same time. The horse trailer has electric brakes & 12V aux power, the camper needs aux 12V power. I have the brake lead hooked up to the brake post (under hood fuse box) and one of the 12V power feeds hooked up to the 12V aux power feed post (at the under hood fuse box) all works well, just wondering what the third wire labeled "Aux Trailer Power Feed" is.

Just this morning I discovered an issue. It seems that the camper refrigerator (3way powered - LP gas, 120V AC or 12V DC) wants it's own dedicated 12V power feed. It appears that when the camper is plugged into the truck the electric brake feed is wired to the 12V DC refer power. So now I'm looking for an additional 12V AUX power feed for the camper. When I find it I'm not sure how I'm going to get it there as I'm already using all 7 wires of my 7 pin trailer plugs....any thoughts or ideas? I am currently using the rear 7 pin recepticle with a Y adapter I found online to plug both the trailer and the camper in at the same time.

If there is another 5th wheel trailer lead on the left side of the truck this would solve my issue; can you tell me where I can find the wire?
Thanks,
John
Thanks,

I will comment on the trailer 12 volt power that is to the refrigerator and other camper on board devices. with this I would run another 12 volt feed wire and ground for the 12 volt source of the camper. properly fused and with 6 ga. wire.

the long run to the camper is why you need larger sized wire to handle the high amps with the low 12volts. also any inverters in the camper will require high amp capacity wire. 6 GA should do it for 40 amps over 20 feet.do a quick wire run around the vehicle to test out first then properly wire into the frame / body to the camper.

the aux feed wire gm uses is not that good for high amps..

[jwichman]

Originally Posted by j cAT

I will comment on the trailer 12 volt power that is to the refrigerator and other camper on board devices. with this I would run another 12 volt feed wire and ground for the 12 volt source of the camper. properly fused and with 6 ga. wire.

the long run to the camper is why you need larger sized wire to handle the high amps with the low 12volts. also any inverters in the camper will require high amp capacity wire. 6 GA should do it for 40 amps over 20 feet.do a quick wire run around the vehicle to test out first then properly wire into the frame / body to the camper.

the aux feed wire gm uses is not that good for high amps..

The camper and trailer are factory wired. I just discovered that the the DC refer circuit was utilizing the electric brake pin of the 7 pin connector. All other appliances utilized the aux feed pin of the 7 pin or 120V when plugged into house power.
40amps sounds too high for this circuit. The refer will only run on DC while traveling and no other appliances or lights on the aux feed will be energized during travel. Essentially it will have it's own dedicated circuit when run on DC. The refer DC heating element is 150W (~12.5A) and has a 15amp fuse in place. If my memory serves correctly the fuse for the aux power feed in the truck is 20A.

[j cAT]

Originally Posted by jwichman

The camper and trailer are factory wired. I just discovered that the the DC refer circuit was utilizing the electric brake pin of the 7 pin connector. All other appliances utilized the aux feed pin of the 7 pin or 120V when plugged into house power.
40amps sounds too high for this circuit. The refer will only run on DC while traveling and no other appliances or lights on the aux feed will be energized during travel. Essentially it will have it's own dedicated circuit when run on DC. The refer DC heating element is 150W (~12.5A) and has a 15amp fuse in place. If my memory serves correctly the fuse for the aux power feed in the truck is 20A.

the ability of the wire to handle the amperage is important. the resistance of the wire however is the problem with 12 volts. the lower the voltage the larger the wire size is required over a long run. resistance of the wire is the problem . 12 volts is low pressure. now 120 volts no problem you can get away with smaller sized wire.

the way to see if your wire has the proper ability to handle the load would be to run the camper equipment and in the camper measure the 12volts input to it . see how much voltage drop you get. now on the fusing of the 12 volt feed wire you do no require a 40 amp fuse just use a 20 amp size with the larger wire. the larger wire is to reduce voltage drop. also using the body as a return path is not good. running a ground wire to the rear of the vehicle will reduce voltage drop .

[jwichman]

Originally Posted by j cAT

the ability of the wire to handle the amperage is important. the resistance of the wire however is the problem with 12 volts. the lower the voltage the larger the wire size is required over a long run. resistance of the wire is the problem . 12 volts is low pressure. now 120 volts no problem you can get away with smaller sized wire.

the way to see if your wire has the proper ability to handle the load would be to run the camper equipment and in the camper measure the 12volts input to it . see how much voltage drop you get. now on the fusing of the 12 volt feed wire you do no require a 40 amp fuse just use a 20 amp size with the larger wire. the larger wire is to reduce voltage drop. also using the body as a return path is not good. running a ground wire to the rear of the vehicle will reduce voltage drop .

I agree with all of your suggestions however my initial question was where is the end of the second "trailer aux power feed" that starts at the under hood fuse box. This wire is just hanging under the good in the same vacinity as the elec brake wire and must be terminated on one of the two aux power post of the fuse box. I've looked underneath drivers side near the head end of the PU box & didn't find it. Anyone else have this duplicate wire?