Trailer Electrical Connector - Montana Owners Club

Cat320 · 02-19-2007, 02:57 PM

On our last TT, when the trailer was mated to the truck via the standard pig tail, with the battery removed, all the 12v items worked. Today, I went to the Montana to do some minor repairs, hooked up the pig tail (battery was home in the garage), got no 12v power at all...truck running or not, no difference. Is this normal for Montanas/Keystone?

Dave e Victoria · 02-19-2007, 04:08 PM

This looks like a new truck? Have you checked to make sure the truck has a fuse in the "post 1" location? This fuse is not installed on new GM trucks from the factory. On our 2006 the fuse is about 1/2 inch square and is located in the fuse panel under the hood on the left side of the truck. The fuse is in the top most row all the way to the left. My truck had a paper sticker over this area and made the lake of a fuse not so obvious. The fuse is a 40 ampere rating and is available at most auto supply stores.
Dave

LonnieB · 02-19-2007, 04:22 PM

Bert,

Have you checked the battery disconnect switch in the docking station?

Broome101 · 02-20-2007, 01:15 AM

I would bet Dave is correct.

Cat320 · 02-20-2007, 01:13 PM

The fuse is fine, I put it in months ago. The truck is an 07 Classic, but I've towed the Montana nearly 6000 miles, the pig tail has worked fine (trailer brakes, lights, etc).

Are you guys telling me the 12v stuff should work with no battery? If so, have you tried your rigs (with no battery)? It's as if the truck's 12v power goes through the battery to the camper...since the battery is not there and all the wiring is off, the 12v power can't go anywhere.

keham · 02-20-2007, 01:26 PM

I have a battery disconnect in trailer. only 12v in trailer if ac applied or battery connected. It was this way before the disconnect. TV 12 volt to battery then RV. so I say yes keystone does it that way i know my 01 cougar and this 05 Montana was that way like yours. Hope that helps.

Ps. Thou the outside running brake and tail lights still work with battery disconnect or the battery is out. Now sure how they do that, but I know both mine worked battery or no battery just the TV power. but brake safety switch does need a battery for that to work. And mine were before the docking station built-in battery disconnect. But sounds like wired like mine. Do your outside lights (running) work with just the truck?

bsmeaton · 02-20-2007, 01:46 PM

Figure it out yet Bert? Just curious.

H. John Kohl · 02-21-2007, 02:53 AM

You might check the splicing box where the pigtail is connected to the trailer. Remove the plate over the electrical box and check for a fuse on the red lead pin 4 of the pigtail. A Everest has a 30 amp fuse there. If that fuse is blown you will not get power from your TV to your monty.

Cat320 · 02-21-2007, 01:24 PM

Last night, after my post here, I got a flashlight and went out and checked the truck's 40 amp fuse under the hood...blown! Don't know why. Went to an auto part store today and got two replacements, put one in, plugged in the pig tail and all the 12v stuff now works. My only problem/question now is to figure out why the original fuse blew! It's like there is a fuse gremlin in there...the very first time I used the landing gear...blew the 40 amp fuse...replaced it and has worked fine since. Go figure.

Appreciate the help.

Dave e Victoria · 02-21-2007, 01:43 PM

I have a suspition that the legs have a load that is close to 40 amps when starting. When you have a battery attached, even if it is down some, it carries a small part of the load especially for a transient load. I looks like a big old capacitor in the circuit. Without the battery you just happened to trip over teh fuse rating. Just a guess

The problem with this fuse is it is subject to latent failure. That is, if it is blown there is no indication until you need it. A good reason to carry a spare.

bsmeaton · 02-21-2007, 02:17 PM

Bert,

I think Dave is right. The landing gear and the slides are too much of a load for that charge line. That came up on another post where someone kept blowing the fuse with the slides because they didn't have the batteries hooked up.

Broome101 · 02-22-2007, 01:42 AM

Your lading gear has to 50 map circuit breakers in series to give you 100amp protection, if you had no battery wired in and only running off tow vehicle you bypassed the circuit breakers on the Monty and more than likely that's what pop your truck fuse. Those CB have red rubber covers over them usually close to where the battery is mounted to the head wall behind battery. Just a guess.

kmh3212 · 02-23-2007, 02:20 AM

Bert,
The landing gear and the slide electrical load becomes a problem with the small guage wire you have running to the back of the truck as well as the pigtail. On that long run the 12 volts drops to a lower voltage and that causes amperage to go up over the capacity of the 40 amp fuse. The battery really needs to be in place when you run these high electrical loads.
Fuses do wear out as well.
You got her fixed now and good information for all.
Kevin

Cat320 · 02-23-2007, 01:30 PM

Thanks for the thoughts guys. I'm getting so smart it's scary!

nkwist · 02-23-2007, 05:08 PM

I had removed the house battery (and didn't have it with me) when I had to extend the slides the other day. I used the TV connection and it extended the slides OK. I guess I'm lucky I didn't blow a fuse, but they did extend with the battery missing from the 5w.

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