# Truck Not Charging Camper Batteries



## Wolfpackers (May 31, 2007)

Well, we've begun our trip out west and have the newly installed 6 volt Trojan batteries. After installing the batteries, I dry camped 2 nights and the voltage dropped from 12.8V to 12.5 or so. When we left on the current trip, the voltage was reading 12.37V and after towing for 530 miles, the voltage reading was still at 12.37V. While hooked up and with the truck running, the voltage was still only reading 12.37V during those first 500 miles.

We're currently on shore power and the voltage is reading 13.77V. I want to ensure the batteries are being charged as I am towing as we may be dry camping in Utah in a few weeks.

How do I determine if the connector on my truck is sending a charge voltage to the 5'er ?

Thanks,
Brent


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## CamperAndy (Aug 26, 2004)

Check the pin out on your connector, if you do not see voltage on pin 4 you need to check the fuse box on your truck. Some trucks require a relay be installed. You may want to check your owners manual to see if it mentions a requirement for a relay. My Ram has power there all the time but some require that the truck be running.


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## Oregon_Camper (Sep 13, 2004)

My Suburban came with the "tow package" which means the fuse Andy is talking about was included with the Suburban, but it was still wrapped up in some of the wiring. (meaning it was NOT installed when I drove the Sub off the lot)

Shop found the fuse...installed it (free) and I was on my way.

I has an Expedition prior to this Suburban and it cost my about $75 to buy that darn fuse from them to charge my battery in my Coleman pop-up.


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## jaystermeister1 (Apr 18, 2007)

I have a 2006 duramax and I had the same problem. There is a dummy fuse in the fuse box that needs to be replaced with a real fuse. When I bought my car the fuse came with the wire harness that is used to hook up my prodigy. It was wrapped up in the wires and I didn't even know that I was supposed to put that fuse in my fuse box. Hope that is the problem.


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## Wolfpackers (May 31, 2007)

I knew that a fuse may be needed, but since the trailer lights work when towing, I assumed the installer had put the fuse in. My Chevy came with the tow package and also had a 5th wheel wiring harness which I had the hitch installer run to a new plug in the rear side wall of the bed. I'll check the manual and fuse location to see if I can find ze probleem.

Edit: When I had the 12v battery and no voltmeter plugged into the 12V socket in the bedroom, I always noticed that my "meter" showed more lights after towing than before, so I figured that the battery was getting a charge during towing.

Thanks guys,
Brent


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## gregjoyal (Jan 25, 2005)

Everything but the 12V works without the fuse... My truck didn't come with any wiring harnesses or fuses as I bought it used... I bought the fuse from my local chevy dealer for 7 or 8 bucks a few years back. Just remember there is a dummy plug or you'll be wondering where to stick it. (besides up chevy's ... for cheaping out on a single fuse)

Someone correct me if I'm wrong, but when a battery is being used, the battery heats up, and some power output is lost... When you stop using it, as the battery cools, some of that output returns which is possibly why you had some bars return. I did that once with my boat - used the battery for my electric trolling motor and under estimated how much juice it took to start the boat. I had to wait about 30 mins for the battery to cool down enough and all was good (my fishing partner was none too impressed with the possibility of being stranded at the far end of the lake on a day with little to no boat traffic).


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## Wolfpackers (May 31, 2007)

I think I've found the answer to the charging issue. I stopped at a Chevy dealer in Henryetta, OK and they gave me a 40A fuse to plug in, but could not find an empty fuse slot for a 40A fuse....however I did spot a spare wire taped up to a harness hiding between the fuse box and the front fender. It was labeled "Aftermarket Trailer 12V Feed" or something similar. I haven't gotten a chance to connect it to a 12V terminal yet, but am hoping to check it out in the AM. Will post results.


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## Oregon_Camper (Sep 13, 2004)

Wolfpackers said:


> I think I've found the answer to the charging issue. I stopped at a Chevy dealer in Henryetta, OK and they gave me a 40A fuse to plug in, but could not find an empty fuse slot for a 40A fuse....however I did spot a spare wire taped up to a harness hiding between the fuse box and the front fender. It was labeled "Aftermarket Trailer 12V Feed" or something similar. I haven't gotten a chance to connect it to a 12V terminal yet, but am hoping to check it out in the AM. Will post results.


did you pull the fuse out? Reason I ask, is the covers they use for the actual fuse, looks just like a fuse...except it isn't.


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## MI Outback (Sep 24, 2007)

On the 07/08 Silverados the 12v+ wire for a brake controller and charging through the trailer connector are not connected in the fuse block under the hood. You will also need to add a 4OA fuse in the block for the trailer charging circuit. If you pop off the fuse panel cover you will see two post on the front of the block. The post closest to the fender is for the trailer charging wire (red wire w/ black stripe...it is taped to the wiring harness below your master cylinder). The other post is for the 12v+ that goes to a brake controller. It has a 30A fuse, usally instaled from the factory. That wire (red w/ black stipe) is located between the fender and the fuse box. The posts do not have nuts on them so you will have to buy those along with the 40A fuse.

Let me know if you have any questions, I just hooked mine up this past weekend. I could take some photos and email them to you.


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## California Jim (Dec 11, 2003)

Ah yes. I remember this well as I too have a 2007 GM vehicle. You can read THIS POST for more detailed info and my adventures with the wire & fuse hook-up.

Jim


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## Wolfpackers (May 31, 2007)

MI Outback said:


> On the 07/08 Silverados the 12v+ wire for a brake controller and charging through the trailer connector are not connected in the fuse block under the hood. You will also need to add a 4OA fuse in the block for the trailer charging circuit. If you pop off the fuse panel cover you will see two post on the front of the block. The post closest to the fender is for the trailer charging wire (red wire w/ black stripe...it is taped to the wiring harness below your master cylinder). The other post is for the 12v+ that goes to a brake controller. It has a 30A fuse, usally instaled from the factory. That wire (red w/ black stipe) is located between the fender and the fuse box. The posts do not have nuts on them so you will have to buy those along with the 40A fuse.
> 
> Let me know if you have any questions, I just hooked mine up this past weekend. I could take some photos and email them to you.


As I'm posting, I can't see your signature to see if you have the 2500HD or 1500, so that may account for some of the below.

My Silverado 2500HD has the integrated brake controller from the factory (and it works great!). The wire from below the master cylinder is hooked up to the silver stud, not the one closest to the fender as you indicated. I don't know if the factory did this or the hitch installer, who also added a 7 pin plug inside my truck bed. There does appear to be some electrical tape under the master cylinder as if the wire was taped up at some point. That wire has the flexible covering on it all the way to the silver stud. The wire between the fuse box and fender was still taped up until I found it a while back. It's not currently connected to anything and does not have any flexible cover on it.

I don't see a place to install a 40A fuse in the fuse box under the hood...what am I missing? A dealer in OK gave me a 40A fuse, but not finding a place to plug it in, I gave it back to him. Unless there are different 40A fuses with different spade spacing, I don't have a 40A fuse spot available and don't recall there being a 40A fuse in the box at all. I'm currently in Moab, UT and there is a small Chevy dealer here, but I wouldn't expect an immediate, correct answer from them based on my experience and those of other OB'ers.

What happens if I connect both wires to the same stud? I know the wire near the fender will fit over the silver stud and so will the other wire, as that's where it's connected now. I did connect the wire from near the fender to the silver stud along with the other wire, but did not get 12V at the connector. One dealer told me I had to have my headlight on, not daytime running lights, and tow/haul on in order to get 12V to the trailer batteries....did yours?

What should I do next? Luckily, we haven't had to dry camp this trip except the first nite at a truck stop and 3 nites at a friends house in cool weather, but would like to have everthing hooked up correctly in the event we do dry camp. We were scheduled to dry camp at the south rim of the GC, but was able to get sites with hookups and canceled the Mather reservations.

Thanks,
Brent


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