Electrical Short in 2016 Yukon XL Denali (possibly trailer receptacle)

[pcrai001]

I seem to have an electrical short somewhere. It started a few months ago when I would leave a trailer hooked up for a long period of time. If I hooked up a trailer (any type - boat, camper, utility) overnight it would drain the battery to a point where sometimes I would have to get a jump start. After that I noticed the marker lights stopped working. I troubleshot that and found a blown fuse. Now, it is struggling to start even if I don't have a trailer hooked up. I did a diagnostics on battery, starter (I first thought that might have been it) and alternator and all are good. I'm going to check the wiring to the trailer receptacle... but I was wondering if anyone else has had this issue and if you may know what the problem is.

Thanks!

 

[RoadTrip]

If you left it hooked up to the trailers overnight and the vehicle battery was dead, there is a short in the trailer wiring.

What kind of connections are you using? 7 pin? 4 pin via an adapter? Is the adapter still plugged into the trailer connector socket?

Does your Yukon have the trailering wire and brake option from the factory? Had you used these trailers before with your Yukon without any trouble? Have these trailers been used by other vehicles without problems? What connections were those vehicles using to the trailers?

 

[pcrai001]

I do believe there is a short in the trailer wiring receptacle. I use 7 pin adapter, but I do not leave it in when I don't use the trailer. With that said, it seems to be having the same electrical issue (struggling to start) when the adapter is not in now a days when it used to just struggle when I left the receptacle in. I've been using the same trailers for years with no issues.

 

[Fless]

If the "hotel" circuit in the trailer connector is anything like earlier models, it's live all the time. Key off, on, anytime. Depending on what's being powered in the trailer, like another battery or device, that could drain your truck battery. Also if you have a brake trailer controller it could be staying awake instead of going to sleep (like it should) after a while.

Can you be more specific about what is meant by "struggling to start?" No crank? Slow crank? Does it start after it cranks for a bit?

A parasitic draw test might be a good thing to do.

 

[RoadTrip]

On a 7-pin connector, one of the pins supplies battery power to the trailer — for those that are wired to accept it — so you should disconnect the battery and disassemble the vehicle’s connector to remove any water or corrosion inside that is likely shorting the battery feed to ground.

 

[pcrai001]

If the "hotel" circuit in the trailer connector is anything like earlier models, it's live all the time. Key off, on, anytime. Depending on what's being powered in the trailer, like another battery or device, that could drain your truck battery. Also if you have a brake trailer controller it could be staying awake instead of going to sleep (like it should) after a while.

Can you be more specific about what is meant by "struggling to start?" No crank? Slow crank? Does it start after it cranks for a bit?

A parasitic draw test might be a good thing to do.

By struggling to start, I mean its a really slow crank. It does start, but the crank is so slow sometimes that I'm surprised it startes sometimes.

 

[pcrai001]

On a 7-pin connector, one of the pins supplies battery power to the trailer — for those that are wired to accept it — so you should disconnect the battery and disassemble the vehicle’s connector to remove any water or corrosion inside that is likely shorting the battery feed to ground.

I'll try that and see what happens. Thanks!

 

[pcrai001]

By struggling to start, I mean its a really slow crank. It does start, but the crank is so slow sometimes that I'm surprised it startes sometimes.

So something you mentioned reminded me that I left my camper hooked up to the truck overnight and I noticed that me exterior LED lights were still on after a couple of hours I turned the truck off. The camper batter disconnect was off. Once I unplugged the camper from the truck eletrical receptacle the LEDs turned off. So that tells me the power from the truck battery is staying on to the camper when it shouldn't be. What would be the fix?