So I’ve had this situation before and paid a shop to fix it and no recall what they did. I get 12v on the inside of the “U” shaped paddle (brown wire driving lights) on the inside (see red arrow) but zero volts on the outside which is where the flat panel on the male plug makes contact. I exposed all the wires about 12-18” from the female receptacle on the bumper and found one bad section in the brown wire. Cut it back to good clean metal, connected everything and the same result. Bought a Dorman replacement female receptacle. $28 vs $79 for the same product both are made by Pollak. Same issue on that “U” shaped paddle. Any idea why I’m not getting 12V to the outside of the paddle? I checked both blinkers and they have equal voltage on both sides. Thank you.
02 Duramax driving lights not working at trailer plug
- Thread starter Mcguirejohnson
- Start date
I'm not a fan of those trailer connectors. I always seem to have to bend the terminals to make better contact. They suffer from corrosion and are stiff and hard to insert and pull out. Try spreading the pins out a little more and see if it helps
And I know it will be asked and I should have mentioned that I went through all the fuses. They are all good. I even swapped this one for a new one just to verify
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Correct. I even get 12v to the pin connector on the female side (mounted under the hitch). But only on the inside of that pin. it’s double sided as it’s bent into a “u” shape. All other pins on the female side get 12v on both sides of the pin. I have a red arrow pointing to that pin in the original post. Problem is the male 7-pin connector only makes contact on the outside of the female pins.
It’s not that the male connector pin is not making contact. Issue is the female pin does not register 12v on the outside where it makes contact.
Then it's got to be corrosion or some coating that's blocking the current. It's the same piece of metal on the inside to the outside. As you said it's a U shaped piece of metal. Try a little sand paper on a stick or an emery board, etc to try and clean it up
You know you can replace that plug receptacle right? It's less than $20 too depending on where you purchase it from. Polak part number 11916
I believe the Pollak part is the same as the OEM.
For reference you can see it here and they have a few videos on it.
If you like paying 2x more you can get it under the Dorman OE Solutions Part number 924-307
And if you really want that great GM feeling 12191503
I like to add dielectric grease to the harness plug when I change out the receptacle.
I believe the Pollak part is the same as the OEM.
For reference you can see it here and they have a few videos on it.
If you like paying 2x more you can get it under the Dorman OE Solutions Part number 924-307
And if you really want that great GM feeling 12191503
I like to add dielectric grease to the harness plug when I change out the receptacle.
I used a .22 cal bronze brush gun cleaning attachment to clean my female contacts. This may not solve your problem but it it sure is cheap and easy.
I should have clarified this, but my male 7 pin connector (trailer side) as well as my bumper mount female side are both brand new. And the u-shaped tab on the Pollak female receptacle is performing the same way. Juice only on the inside of the tab. So I bought this heavy duty male plug that fits over the pin hitting both sides of the U. Still zero volts beyond. There has to be something going on between my bumper and inward on the truck. It has to be something simple that I’m overlooking. 
So I do not have the tools to do a load test. If my volt meter can do this I have no idea how that works. I did test the brown wire as it leads into the back of the clip that connects to the female hard mounted clip. I get 11.85+ volts consistently (engine not running) which is the same measurement I get on the metal u-shaped tab.
So I jumped the brown wire from under the bumper directly to the trailer harness and it’s like a Christmas tree. Cut out the harness clip and have it on the bench. 100% ohms out to the trailer pigtail. Even both sides of that U-shaped pin on the female connector ohm out. But only 12v on the bottom of the tab when wired into the truck harness. I have a few good friend who are trailer harness experts and they are completely stumped
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Great suggestion. But with brand new male and female connectors the only connector left to evaluate is the plug end of the GM harness. For $20ish I just ordered this Hopkins product and will install next week after I get back from a quick trip to CO. Will report back to the group the results.
What cab/bed configuration is your truck?
The reason I ask is the early 1500 trucks like a 99 2000 Didn't always get built with a heavy duty towing package. They sold a wiring harness kit you would buy to add the 7 pin trailer harness to the truck. It plugged in at the fuse box and ran all the way to the back of the truck. Same with the hitch you buy a hitch kit that came with all the mounting hardware.
GM #12495932 is the trailer wiring kit. It comes with a complete harness ready to plug in and the instructions. I am pretty sure it came with the actual 7 pin connector too... Some of the Images show that in the kits floating around.
Gm states in the up fitter document that it does. I will attach that page of it. The wiring harness kit #12495932 comes with universal under body harness 12463530 with a 7 way connector and instructions #12463639
I have a kit some where I would have to dig it out to look at it.
The reason I ask is the early 1500 trucks like a 99 2000 Didn't always get built with a heavy duty towing package. They sold a wiring harness kit you would buy to add the 7 pin trailer harness to the truck. It plugged in at the fuse box and ran all the way to the back of the truck. Same with the hitch you buy a hitch kit that came with all the mounting hardware.
GM #12495932 is the trailer wiring kit. It comes with a complete harness ready to plug in and the instructions. I am pretty sure it came with the actual 7 pin connector too... Some of the Images show that in the kits floating around.
Gm states in the up fitter document that it does. I will attach that page of it. The wiring harness kit #12495932 comes with universal under body harness 12463530 with a 7 way connector and instructions #12463639
I have a kit some where I would have to dig it out to look at it.
Update for all reading. The Hopkins harness replacement fixed my issue. I do have the heavy duty factory setup and this is a perfect replacement (and the price is reasonable). For whatever reason the harness plug that connects to the back of the Pollak female outlet (hard mounted under the bumper) failed. Thank you to everyone for your input.