7 pin plug 12v direct current

Yes, it can be used to charge the camper batteries.
Yes, on GMs it is a good idea to unplug the cable as it could drain the trucks battery. Better is to add a relay so you don't have to unplug and plug back in.
Relay would go between the fuse and the camper plug. Energizze the relay from an igntion switch on position source.
You may read through this thread as it is about the same situation as you have.
Thread

Yes it will charge the battery in the camper. I would skip the relay for a while. You may find you like having the 12V hot all the time like I did (I actually removed a relay after a while).

We attempted to cover that in your previous post. Installing the solenoid is what prevents the camper from drawing down the truck batteries.

Thanks again for the precious comments
Gaetan

Scott the camper batt. will keep the wires hot even if the relay is open.

I too have the charge wire from the truck to the TC. I put a toggle switch on it over eight years ago, and have never turned it on. I have a list of reasons not to turn it on, and really see no need to. At one time I considered the cost and benefit to upgrade the truck's charging system. I decided my money would be better spent toward solar for the TC.

Wayne

Once you go solar you will never not have one, trust me....but the OP asked about "basically" the charge wire in a seven pin arrangement. It depends on the truck to start with....some have a built in solenoid, others you have to install an aftermarket one but a "HOT" wire at the plug is usually there. You can very easily get in trouble if it is hot all the time...you will pull power from the truck battery...a very bad thing. Best advise is to use a volt meter to check it at the plug to know what you have going on. The advantage is that if you don't have solar your battery will charge while you drive, but not a very reliable source as your alternator is not going to keep up in most cases.

KKELLER14K wrote:
The advantage is that if you don't have solar your battery will charge while you drive, but not a very reliable source as your alternator is not going to keep up in most cases.

What makes you think that? It was true in the 60's, 70's and 80's, but not anymore. The 55-65A alternator with pathetic idle output found in that era turned out to be insufficient as EFI with electric fuel pumps became the norm.

As of the 90's, all three switched to 100+A rated alternators. They also pumped up the idle current rating. My truck has a 135A alternator that pumps out 90A at idle. Gone are the days of dim headlights when idling with the heater on high.

I certainly won't bash solar - good for those of you that went that route. I put $150 into having a 4 gauge wire from the alternator to the camper batteries and it works well when driving every few days. It's a cheap alternative to solar with almost as good results.

If you choose to unplug the seven pin connector while camping, make sure you plug it back in when you're driving again. It also powers the brake, turn, and running lights on the camper.