Trailer plug ground wire location

[MrBean]

Anyone able to definitively say where the ground wire for the 7-pin trailer plug is attached to the frame of a 2019 Ram 2500? All the wires go into a harness together, ground included, and I don't see the ground wire leave the harness and attach to the frame anywhere.

My turn signal/brake lights aren't working and checking with a multimeter the connectors don't have power, but I've confirmed the other connectors have power (including the 4-pin turn signal connectors). I'm thinking it's got to be the ground wire, but it's too hot out to be under the truck for hours looking for it.

Hopefully y'all can help!

 

[crash68]

If the 7 pin doesn't work but the 4 pin does, then it's the jack in the bumper. You can pull the plug out of the back and check power there.
The truck tail lights and the trailer light circuits are two separate circuits with individual grounds.

 

[Tulecreeper]

If your 7-pin doesn't work but your 4-pin does, the problem is after where they split off from each other behind the bumper. If neither of them worked, then it would be farther upstream.

Example: If your main harness is running to your 7-pin connector and they have just spliced the 4-pin into that a foot before the 7-pin plug, then your problem is in that 1-foot section between the splice and the 7-pin connector.

 

[KeithP]

Anyone able to definitively say where the ground wire for the 7-pin trailer plug is attached to the frame of a 2019 Ram 2500? All the wires go into a harness together, ground included, and I don't see the ground wire leave the harness and attach to the frame anywhere.

My turn signal/brake lights aren't working and checking with a multimeter the connectors don't have power, but I've confirmed the other connectors have power (including the 4-pin turn signal connectors). I'm thinking it's got to be the ground wire, but it's too hot out to be under the truck for hours looking for it.

Hopefully y'all can help!

If all but the trailer/turn lights are working it’s not likely the ground. Your trailer turn/brake lights are fused separately. Check that first.

 

[Tulecreeper]

If all but the trailer/turn lights are working it’s not likely the ground. Your trailer turn/brake lights are fused separately. Check that first.

Yes, but the same fuse is used for both the 7-pin and 4-pin brake turn/lights. If it was a fuse problem he would have the same issue on both connectors.

 

[18CrewDually]

Unplug and check the connection at the back of the 7rv receptacle. See if your turn lights work there on the harness side with a meter or test light. If it does then it's the receptacle or plug connection.

 

[GTyankee]

I think there 2 types of 7 pin plugs

Does your trailer have electric brakes ?
Does your trailer have back up lights ?

How to Wire a 7 Pin Trailer Plug (Vehicle Side)

Trailer wiring can be one of the most intimidating components of your towing setup, but it doesn't have to be. Most of us aren't electricians, but that doesn...

www.youtube.com

no pin functions will work, unless you have a GROUND

 

[GTyankee]

from a previous post

2018 Ram 1500 7 pin Wiring diagram???

I looked in the owners manual and searched on line. Does anyone have a wiring diagram showing what pins are what on our 4th Gen Rams for the 7 Pin Connection? Thanks All.

www.ramforum.com

 

[KeithP]

Yes, but the same fuse is used for both the 7-pin and 4-pin brake turn/lights. If it was a fuse problem he would have the same issue on both connectors.

Re-read the OP. I didn’t catch that. Still don’t think it’s a ground issue. I work for U-Haul. We have 192,000 fleet trucks with 7/4 pin connectors on them. I’ve seen plenty of these have internal failures. He probably needs to change his out. They’re not expensive and easy to swap out.

 

[Tulecreeper]

Re-read the OP. I didn’t catch that. Still don’t think it’s a ground issue. I work for U-Haul. We have 192,000 fleet trucks with 7/4 pin connectors on them. I’ve seen plenty of these have internal failures. He probably needs to change his out. They’re not expensive and easy to swap out.

The OP didn't say it, I did. I don't think it's a ground issue either. And I don't think it's a fuse issue or it would affect both the 7 and 4-pin connectors because (for example) they don't have separate fuses for the brake lights/turn signals; they both use the same fuse(s). I think there is a disconnect/broken wire going to the 7-pin right about where the 7-pin and 4-pin harnesses tie into each other.