Originally Posted by Trogdog
TV is a 2008 Jeep Rubicon. Trailer battery was all but dead at the end of a two day camp trip. I left the fridge off on the way home, and by the time I got home five hours later the battery had enough juice to run both the lights and the fan. I'm guessing this means the charge line is hooked up?
Maybe. It's not hard to tell if your battery lead is connected thru your
7 pin plug.
The surest way is to simply disconnect your trailer battery at the battery.
Remove one battery lead.
Turn on a light inside the trailer. The light should NOT come on!
Now plug in the trailer to your Jeep. If the light comes on inside you
are connected to your engine battery as it should be.
Note- at times I have been known to plug my truck back into the trailer
on the last day of a long weekend in order to get a little extra juice to
finish out the trip. Careful, you can wind up needing a jump start but so
far I've been lucky
Note 2- some folks tow vehicles have built in relay so the engine battery
is not connected thru the trailer plug unless the engine is running.
In this case to do my test above, you'd need to start the truck.