No Power to 7-Way Plug?

I may have been a bit misleading. So It is an isolation switch that you install usually on you firewall and beef it up with a bigger charge wire than stock. It is powered directly from the truck batteries. When you turn on the truck, the isolator opens the flow of power. When you turn it off, obviously it closes the flow of power beteen the truck and RV. The reason I set up my 2 sytems was first, I could deliver more power to the TC. Again running dual batteries in the truck and the TC. So I used the stock bummper 7 pin to plug in my boat so I could keep some power going to the boat batteries...just redundicy and peace of mind. That bumper connection is also isolated but just not as powerful. ....HEY! congrats you are getting a good education.

Now you are learning RV stuff. congrats.

If you really need to charge the camper battery from the truck, then you can use bigger wire, and not go through the thin wires around the fuse box. Make sure that stud #1, that some say is on all the time, is NOT on all the time or if you forget to unplug the trailer from the truck you could run down your truck starting battery. You need the trailer 12 volt power to be connected to the ignition somehow, and not straight to the on-all-the-time battery. Sounds like previous owner did some home-brew electrical kanosh work...
but you got it working, so good nuff for now...

Other option is a DC to DC charger.

Good to hear. Thanks for checking back with the results.

I FIXED IT!! Turns out because the previous owner had a rear bumper plug and a side plug, there were separate power wires to stud #1 on the underhood fusebox. When testing power to the stud, I happened to be perfectly positioned to see the other power wire, and when I connected it, the battery started getting charged!

Thanks for the help everyone!

I agree about replacing the seven pin but start with the trailer's. Has always solved all my issues.

wnjj wrote:

stupendous_man wrote:

wnjj wrote:
When you say, “adding a fuse”, did you add an inline fuse or did you populate the fuse in the fuse box that powers up stud #1? Did you make sure there is power where you connected the wire?

Thanks for the reply! I populated the fuse in the fuse box to power stud #1, but I didn’t check if there was power to the wire. I’m not sure how to do that, but I did check the fuse with the multimeter and it was good. To check the power on the wire, would I take a voltage reading with the multimeter with the black probe on the truck frame and the red probe on the power wire while the truck is on??

Yes, but you don’t even need the truck on as stud #1 is on full time. I installed an automatic isolator (solid state) between the stud and the wire. Before that I would pull the fuse in camp so I didn’t run the truck down. You can unplug at the rear bumper easy enough. My truck also has an in-bed plug connected to the harness you mentioned that is stowed behind the cab. Both 7-way plugs are connected to the same place.

Ok! I’ll try testing the power wire tomorrow morning and report back (probably the late morning because it’s already past 1am). That’s a slick method with the isolator. I like your budget option too, perfect for a ski bum like me. Good night!

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stupendous_man wrote:

wnjj wrote:
When you say, “adding a fuse”, did you add an inline fuse or did you populate the fuse in the fuse box that powers up stud #1? Did you make sure there is power where you connected the wire?

Thanks for the reply! I populated the fuse in the fuse box to power stud #1, but I didn’t check if there was power to the wire. I’m not sure how to do that, but I did check the fuse with the multimeter and it was good. To check the power on the wire, would I take a voltage reading with the multimeter with the black probe on the truck frame and the red probe on the power wire while the truck is on??

Yes, but you don’t even need the truck on as stud #1 is on full time. You can also put the black probe on the negative battery post if it’s nearby (or use a piece of wire to get there).

I installed an automatic isolator (solid state) between the stud and the wire. Before that I would pull the fuse in camp so I didn’t run the truck down. You can unplug at the rear bumper easy enough. My truck also has an in-bed plug connected to the harness you mentioned that is stowed behind the cab. Both 7-way plugs are connected to the same place.

wnjj wrote:
When you say, “adding a fuse”, did you add an inline fuse or did you populate the fuse in the fuse box that powers up stud #1? Did you make sure there is power where you connected the wire?

Thanks for the reply! I populated the fuse in the fuse box to power stud #1, but I didn’t check if there was power to the wire. I’m not sure how to do that, but I did check the fuse with the multimeter and it was good. To check the power on the wire, would I take a voltage reading using the multimeter with the black probe on the truck frame and the red probe on the power wire stud while the truck is on??

KKELLER14K wrote:
Replace the 7 pin....and work your way back to the front..It could be something so simple like a ground wire.....keep at it. You will find the fail. 7 pin plugs go bad all the time..when did you use it last? How did you know you were not getting power to the RV?...I'm stummped here...External charging wire? WHY? SO...you have 2x 7 pin connectors? My truck does....but you say your using the rear plug on the rear bumber? This is confusing...if I try to help we all need more detailed info. The TC power is hooked up where? Do you have a battery switch? Connected to the fire wall? For a second plug?
When you have two seperate systems that supply power to an RV it is common that the rear bummper plug will be hot while the rig is running but like mine it is split... When you turn off the rig, the bateries are seperated from the RV. I have a 7 pin on the front interior of my truck bed. I have a 7 pin at the hitch. The wiring at the bed connection is beefed up from the factory because I made that tweek to help make the batteries get more power when we travel.. I hope this makes sence..I was running dual 36 Interstates with a 100 watt sollar. All I needed. I am not going to rule this out...but have your alt checked..It is the prosses of elimitation...keep working you will find it!!!

Really appreciate you taking the time to make a detailed reply!

Should I replace the 7 pin on the truck-side or the camper-side?I bought the camper used, so I haven’t gotten the alternator to power the 7-way at all, but I used the running lights today.

I know I’m not getting alternator power to the RV because when I check across the battery terminals with a multimeter, the voltage doesn’t change after turning the truck on.

The external wire was something that had me really confused too, but after asking on here it’s apparently a small wire that allows power to run from the truck to the 7-way, but for some reason it’s not connected or fused by Chevy out of the factory, so you have to do it yourself.

There sort of is two 7-way connectors, the truck has one in the rear bumper (which I’m using) fully wired up that came with trailer package, but there’s also a bundle of wires under the middle of the truck that you can connect another 7-way to. I had no idea about that one, but I was following the rear bumper connector wires to look if it was broken anywhere and happened to see a wire bundle.

By battery switch do you mean the disconnect switch for the camper? I have one of those, but I think there’s also some kind of switch that disconnects the camper from the truck batteries.

What is a fire wall? Sorry, I’m still learning all the terminology.

It sounds like with two connectors, one is only hot when the truck is on, but the beefed up one is always on? Funny you mention solar because I was just thinking I should just get solar and forget troubleshooting the 7-way! It’s been three weeks of repairs and maintenance with the camper and morale was getting low, so thanks a lot for the encouragement, I really need it!!