So on this 2003 GMC 2500HD that I bought recently I was finally installing the fifth wheel hitch and the brake controller, then I cut the tie straps from the wire harness between cab and box to hook up the fifth wheel plug, but before I did it, I noticed the plug at the back bumper hitch is the same, so installed the fuse into the fuse box under hood, then plugged in brake controller and I had power, then tried pushing the brake pedal and you could hear brakes humming on fifth wheel. So I am wondering if that is the plug I should use, I don't figure I will add the one at the front if this one is already set up and appears to take the load, anyone see any problems with using the factory hook up at the back receiver hitch?I am thinking the wires should be all the same.Any input?Thanks

The factory 7-pin at the bumper will certainly work. Most folks mount the second 7-pin in the bed for aesthetic reasons, not wanting to drape the cable over the tailgate of the truck. I added the second 7-pin in both my current truck and my previous one.

I think the only disadvantage is that the 5ver cable has to hang over the tailgate. I kind of have a problem with that.

I plugged into the bumper plug for 5+ years when I had a 5er, no worries. Now have TT.

The 2011 2500 hd had the wire harness for the bed already there along with bumper plug.....all dealer had to do is mount plug in bed and hook to existing wires....maybe your 2500 hd is prewired too for a bed hitch.....

I plug into the bumper also no issues.

Plugging fifth wheel into bumper plug? | Good Sam Community

TomHaycraft
Explorer
Jun 14, 2015
The factory 7-pin at the bumper will certainly work. Most folks mount the second 7-pin in the bed for aesthetic reasons, not wanting to drape the cable over the tailgate of the truck. I added the second 7-pin in both my current truck and my previous one.
rskeans
Explorer
Jun 14, 2015
I think the only disadvantage is that the 5ver cable has to hang over the tailgate. I kind of have a problem with that.
Jack_Diane_Free
Explorer
Jun 14, 2015
I plugged into the bumper plug for 5+ years when I had a 5er, no worries. Now have TT.
sail2liv
Explorer
Jun 14, 2015
The 2011 2500 hd had the wire harness for the bed already there along with bumper plug.....all dealer had to do is mount plug in bed and hook to existing wires....maybe your 2500 hd is prewired too for a bed hitch.....
rhagfo
Explorer III
Jun 14, 2015
I plug into the bumper also no issues.
RoyB
Explorer II
Jun 14, 2015
ETRAILER.COM has an 7-WAY Extension cable. I used one for awhile with my 5th Wheel with no problems...

I installed the end of the extension up near the tailgate corner of the truck bed on the truck inside side panel... The connector end is routed on down to come out under the bed near the OEM 7-way CONNECTOR. All cables out of sight...

Photos from google search

Roy Ken
partsman01
Explorer
Jun 14, 2015
Thanks everyone, did not realise they made an extension for them.
I do have the wires under truck, just could not see doing more work if the bumper plug would work.
Will see how it goes.
Here is a picture of wires I released between cab and front of box.
Hvyhauler
Explorer
Jun 14, 2015
rhagfo wrote:
I plug into the bumper also no issues.

Same for me... I do have a small towel wrapped around the cord where it contacts the tailgate held in place with tape.
dave17352
Explorer
Jun 14, 2015
I use the bumper plug all the time for years. No problems. Easier to get to also.
valhalla360
Navigator
Jun 14, 2015
Another who just uses the bumper plug.

Had an in bed in the last truck but never used it as it wasn't as easy to get to it.