Brakes Lock Up When Trailer is Connected with New Vehicle

Question:

trailer worked fine with 2004 Nissan titan , hooked up to 2018 gmc 1500 and brakes lock up. my camper works fine with the gmc, I see other post for same problems and i wonder can i switch the blue and black wire on the trailer. also do i need to replace the battery on the lowboy its 6 yrs old. thank you

asked by: Lee

Expert Reply:

Yes, you can absolutely switch the blue brake output and black 12 volt power wires on your trailer. The 7-way on your 2018 GMC Sierra 1500 should mirror the photo I have attached for you below so that is what you will need to abide but so long as the vehicle side and trailer side both match it will be fine. Nissan is notorious for switching these wires at the factory so this is a rather common issue that is easy to fix.

In regards to replacing your battery, there really isn't a stated time frame as there are just too many variances so I recommend just taking it into your local auto parts store and having it tested as they usually provide this service free of charge.

expert reply by: Conner L