12v not hot at 7pin

[sobrbiker]

My ‘02 2500 5.9 gasser has no power at the 12v line at hitch. I’ve got power at the trailer brake plug in cab, and both the 40A fuse and relay in PDC are good (new fuse and I’ve plugged the known working blower relay in the trailer relay slot to check).
I suck at wiring, but have checked that. Are there any other fuses, or are there any common failure points along the line from PDC to hitch plug?
Previous owner did add amp and 700w power inverter in cab, but the power from amp is an added fused line at PDC lug-I don’t know if the trailer 12v line goes in the cab for that to matter.

 

[Mister Luck]

Maybe they only work when the brake pedal is depressed?

 

[sobrbiker]

Maybe they only work when the brake pedal is depressed?

I’m talking about the 12v lead that charges trailer while traveling.
The lights and trailer brake feeds are working as they should.

 

[Mister Luck]

I’m talking about the 12v lead that charges trailer while traveling.
The lights and trailer brake feeds are working as they should.

Not getting 12v at the Electric brake pin in the 7pin connector on the truck

2015 Ram 3500 Tradesman Diesel automatic Ok long story short and 4 weeks later, I tested the 7 Way connector for the trailer tow and discovered that it was not getting 12 Volts to the lead that is supposed to give 12 Volts when the brake is pressed. This lead is the Electric brake lead. All the...

www.ramforum.com

 

[sobrbiker]

Thanks, but I’m in the opposite boat-
I read that thread, and that guys trying to understand why he’s not getting braking voltage, but his 12v constant is fine.
My braking circuit is fine and I’m not getting 12V constant.

 

[Mister Luck]

Thanks, but I’m in the opposite boat-
I read that thread, and that guys trying to understand why he’s not getting braking voltage, but his 12v constant is fine.
My braking circuit is fine and I’m not getting 12V constant.

Seems you mentioned common failure points …

I always keep a 7-pin tester under the back seat. Rolled up to a friends place a while back and they had the whole trailer wiring striped from the trailer trying to figure out why the trailer lights and brakes were not working. I popped my tester into the 7-way and nothing. Checked fuses, all OK. Started with the truck wiring harness from the plug back. Found the connector from the harness to the plug in the rear bumper was not fully seated. Pushed in until it locked and voila', lights and brakes.

 

[Ed Brickey]

My first post on here. I am experiencing a similar issue.
2001 25000; constant 3.5v power on my electric brake control pin at the trailer plug at rear of truck. No power at 12v supply pin. Did Dodge swap these pins? I am using a factory 7 blade plug in tester.
Just acquired this 2500 and have not trailed with it yet.

 

[sobrbiker]

I found the 12v hot terminal toasted at the last connector before plug (C-129). Pulled it out and cut it clean and slid it into back of connector until I find a buddy with terminal tool or more patience than me to replace the terminal properly.