12 volt to 7 pin connector - Montana Owners Club

brooksider · 03-02-2011, 01:11 PM

I have an 05 2500 GMC D/A. I checked the 7 pin connector's the other day(one installed by the factory installed hitch and one in the bed that I installed useing the factory camper wiring.).I have towed for 5 years with this truck and never paid any attention to the 12 volt supply. The batt. is always are charged as I use hook ups of the at the CG and have a 30amp plug at home. Neither one of the 7 pin connectors have 12 volt power. I have new fuses in the fuse block under the hood. I bet some one on this forum has the soulition.
Thanks
Joe

awaywego · 03-02-2011, 01:14 PM

Check it with the engine running. On my Ford the key has to be on to pick up a relay so I cannot draw power from the truck battery unless the engine is running. This helps so I do not need to unplug the trailer when we stop for the night and do not unhook.
Hope this helps.

Clemson1881 · 03-02-2011, 01:15 PM

When you say you have new fuses that may eliminate my suggestion, but GMC/Chevys come with a dummy fuse for the 12 volt power supply. You have to remove it and put a real fuse in. I learned this from a dealer when picking up my camper. They did it right in front of me.

mhs4771 · 03-02-2011, 01:18 PM

I think on some, the wire is there but not connected to the 12V lug at the engine mounted fuse block.

camper4 · 03-02-2011, 01:59 PM

I agree with AWAYWEGO. The truck has to be running. Try that first.

drknapp · 03-02-2011, 02:02 PM

Quote:

quote:Originally posted by mhs4771

I think on some, the wire is there but not connected to the 12V lug at the engine mounted fuse block.

That's the way it was on our '07 when we first wired it up. It was on the front of the fuse box. The wire was there all taped up. Had to remove the tape and bolt it on to a stud that was provided.

edit:

Actually, after thinking about it, there are two. One for the brake controller and the other for the aux power. I was able to find the manual showing the stud locations and made a copy of the layout. It's stud 1 and stud 2 you are looking for.

http://i53.tinypic.com/2ntjw90.jpg

http://i56.tinypic.com/2aje5t.jpg

Exnavydiver · 03-02-2011, 02:39 PM

I just got through helping loua-loua run a new wire to the plug on his Canadian Duramax/Allison. The main wire has multiple poor splices under the bed and over the wheel well. We traced that wire back to the main fuse block under the hood. Because of the poor splices under the bed the wire was badly corroded in many places so we just ran another 12 gauge Red from the #1 Aux stud under the fuse block. everything works fine now....

**Rondo** · 03-02-2011, 03:16 PM

You de man Dave!

twindman · 03-02-2011, 03:51 PM

I have a 2004 Chevy Duramax. The power to the trailer is on all the time. I believe (maybe) Ford and Dodge must be running. I think on Dieselplace.com website/forum they talk about this and have detailed info - i.e. diagram showing which pinout in the bed connecter that has +12V and which is ground, etc.
But the info provided by the others here is correct - regarding the cable not always being connected to the fuse box under the hood.

My fuse was blown last summer, and I replaced it. Cheap one from Autozone, so I got a spare too!

Good luck

brooksider · 03-02-2011, 06:28 PM

I have been hunting for the wire that is supposed to be taped up and is near the master cylinder. I may take Dave suggestion and run a new wire. I think it may be the quickest and probally easier on the mind.I have a roll of # 10 gauge.
I have put fuses in stud #1 & 2. I have tried it with the key on, engine running and headlights on as the manual indicates for more voltage.
Thanks for all the suggestions. If the temp is above freezing tomorrow I will work at it again. Will keep you posted.
Joe

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