The power (hot all the time) circuit in the 7 pin trailer plug on the bumper is only putting out ~4v whether the truck is cranked or not. Is there something that should trigger this to be higher to charge a trailer battery or is there something wrong? I figured it should be 12v.

I would like to use this pin to charge a camper battery but with such little output and small gauge wire, I'm not sure that this will work.

Also my reverse light circuit is also only putting out ~4v

Everything else seems to work fine in my trailer circuit.

Applies to truck in sig. Thanks for input. Will be working on this over the weekend so if anyone has any thoughts, post em up.

 

4 volts compared to what? Where are you checking the ground? To the ground in the plug, or to some other ground?

 

Even with that plug supplying 13.7-14 volts, the wire is too small of a diameter and it takes forever to give the battery a decent charge. The best you'll get is a small "surface" charge.

I run 4 gauge welding cables (with 175 amp slow blow fuse) from the truck batteries to quick connectors for the camper and dump trailer batteries. That gives a very decent charge and if I ever need more power I can hook up the quick connectors and tap into the 2 truck batteries as well.

 

and on top of that, once the batteries on the tv are charged, the voltage regulator will turn off the charging so you'll never get any charging ability out of that. With your voltage readings, I'd bet that your just not getting a good ground/connection. You should always have a good coating of dielectric grease on that plug and socket.

 

If you checked the voltage from the neg to the pos as shown on the 7 pin cover than you should have 12 - 13 vdc. with the truck off. Did you use the dc voltage setting on your meter? (we all make this mistake from time to time). If you checked the voltage correctly and have low voltage, than the wiring harness connector on the back of the 7 pin connector may be corroded. There is also a connector under the drivers floor at the frame by the firewall. Clean and dielectric grease the connectors.

 

Checked at the plug. I'll do some more checking.

 

I am having the same problem. I tested mine and I used the ground pin in the connector. It's showing 8.75 volts. My connectors are clean. I test at the battery and I get 14 volts. Does anyone have any ideas? I'm also trying to charge camper batteries.

 

I can't figure out what is wrong with mine it's putting less than 4 volts. Everything is clean. Anyone know what I can do.

 

Firstly, you'll need to verify whether your low reading is caused by a fault with the 12 volt circuit, or with the ground circuit you are measuring it against. I have made up a long 2 conductor cable with alligator clips on one end for this purpose- you can use this to measure your 12 volt output at the rear of the truck against a known good ground from your battery, likewise you can verify your ground at the trailer connector against a known good 12 volt source.

Once you've determined which circuit contains the fault, you can use the appropriate wiring diagram to work back to the front of the truck until your circuit has good voltage, and isolate the problem area.

 

I'm sorry guys. I try to be good about following up on a solution to an issue that I post up but I completely dropped the ball on this one. I hate that.

I really don't remember what it was that got me the full voltage but chances are it was a ground or some other connector that needed some attention. Mine seems to be working now and I am able to keep my camper battery topped off with the truck. I have the parts to add a heavy gauge charging cable to the camper but have yet to put it on.

I hope you get it fixed.

 

Do you know where I can find a wiring diagram? Thanks.

 

It's on pages 8W-54-2,4, and 6 of the manual pdf. You can typically find the full manual online for free and it's a few hundred megs.

 

Found a way to get just those pages....

Hope this helps.

 

Thank you. I took a long wire and hooked to my neg battery terminal and ran it to the back and hooked it to the neg side of the multimeter. I still had 3.56 or so volts. I ran a ohm test on the neg wire and got 6 ohms. That's not to bad considering the amount of wire it was going through all the way from my multimeter wire and through the truck wiring. Did the same thing on the positive side and didn't get a reading. I hooked my power probe up and didn't have any voltage on it but the negative was good. So I'm thinking I have a broken wire somewhere maybe or frayed. I guess the next thing to do is chase the positive wire back. And see what it looks like.

 

Sounds like you have a good handle on tracking down the solution. The Power Probe is a great tool and it's made for stuff just like this.