Battery will not charge off of vehicle connection

I would start at the truck's connector for the trailer. Find your connector here
http://howto.curtmfg.com/Pages/index.cfm.27.html
And see which pins have the 12 volt supply and ground.
Start the engine and measure the voltage between those pins. You should see well over 12.6 volts. If not, your problem is in the truck.

Plug the trailer into the truck and check the voltage on the batteries. With one battery cable disconnected from the battery you should see that same voltage. It will drop when the battery is connected but still needs to be at least 13 volts to do any charging. A slightly dirty plug or jack at the hitch could be the problem or it could be a poor connection somewhere in the trailer or truck. Or a fuse or battery isolator in either. I would be poking pins into those two wires on either side of the plug/jack to measure the voltage while the trailer battery is connected to the truck in order to tell if the problem is in the trailer or the truck.

karlram wrote:
My converter will charge my camper battery off 110 power, but will not charge off the vehicle while driving like it used to. The converter has a smart charger in it so it should fully charge my camper while driving.
Any thoughts on where to start checking?

Your smart charger on the converter works only when plugged in. It has nothing to do with charging through the hitch while driving. The 7-pin connection from the hitch will only supply about 5 amps for each hour of driving at best.

If you see no charging, the fuse may have blown. There is sometimes a separate fuse for trailer charging just off the tow vehicle's starting battery.

There is also most likely a factory fuse if it is the tow package harness.

First off check the 'charge' line position on truck receptacle for 12V power. When you open receptacle cover the truck charge line is on blade at 1 O'clock position. Ground would be on blade at 7 O'clock position.

Should have 12V between those to blades.......

IF no 12V power..then check under hood for blown fuse (drivers side fuse panel)

There is a large wire running between the chassis and the house battery. Start there. There is a gizmo with now bad-juju connected somewhere in between on that wire.

Otherwise you will be reading the Encyclopedia Britannica as far as 1,000,106 possibilities.

Trace that wire. Find the part, return hopefully with a photo of it and let's go from there.

Stick a voltmeter on the socket for starters. It's a small charge to begin with, and probably not worth expending a lot of effort on.