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NCRog · 03-24-2025, 11:17 AM

We've just purchased a new 2025 GMC Yukon, to replace our existing 2019 towed vehicle. I plan to do a DIY towing set-up.

Already have the Blue Ox baseplate, Air Force One, Demco wireless coachlink, Roadmaster battery disconnect system and SpartanLync TPMS sensors identified and/or ordered. The one outstanding item is the wiring modification to utilize the Yukon's lights when towing behind the coach. For my 2019 Yukon, this was an easy add, Blue Ox made a harness which just plugged into the vehicle's wiring, making it truly plug and play. The most complex part of the install was routing the harness from back to front alongside the existing harness. Unfortunately, Blue Ox don't make such a harness for later model vehicles, so the alternative is finding a way to make a harness with splices work. Of course, with the push for additional technology, this vehicle has a combined stop and "animated" turn rear light assembly.

Has anyone successfully managed to design and implement the wiring necessary to run these lights from the coach's 7 way connector? Can it be done and where are the splice/diode points? Thanks in advance.

Cousin Ed · 03-24-2025, 03:11 PM

I believe the Road Master kit will work for you. That's what I'm using on our "25 Silverado.

Dutch Star Don · 03-24-2025, 05:06 PM

Curt makes one.....

https://www.curtmfg.com/all-products...4/RV+Harnesses

Also, when connecting the Roadmaster Battery Disconnect, ETrailer has a great video for installing it on a GM product. When you look at the battery connections, GM uses a plate that bolts to the positive battery lug. It looks complicated, but it was as simple as loosening the lug, turning 90 degrees and adding a bolt to the plate. Watch the video and you'll see how easy it is to add the two large cables from the Roadmaster unit. I mounted the unit to the firewall near the battery.

NCRog · 03-26-2025, 06:33 AM

Quote:

Originally Posted by Dutch Star Don

Curt makes one.....

https://www.curtmfg.com/all-products...4/RV+Harnesses

Also, when connecting the Roadmaster Battery Disconnect, ETrailer has a great video for installing it on a GM product. When you look at the battery connections, GM uses a plate that bolts to the positive battery lug. It looks complicated, but it was as simple as loosening the lug, turning 90 degrees and adding a bolt to the plate. Watch the video and you'll see how easy it is to add the two large cables from the Roadmaster unit. I mounted the unit to the firewall near the battery.

Don, thanks for the info! After I started this thread I found the info on the vehicle specific Curt harness, looks like it's plug and play ... great! It appears that Curt have both a universal set and also this model specific set ... some websites only show the universal item. I've ordered the one you referenced, they also have very detailed installation info, including where to find the harness connection points. My OCD based plan is to start by connecting just one part of the harness and verify it operates the associated rear lights correctly. If it passes that test I'll start routing the harness alongside the main harness to the front of the vehicle, which I recall was a time consuming job last time. Fingers crossed!

Yes, I used the Roadmaster battery disconnect on my 2019 Yukon. I was able to find some real estate on the fender, under the air filter box to mount it. I agree, the supplied cables are just right and make for a tidy installation. I mounted the push button on the trim around the driver's door, where it transitions up under the dash, I can get to it easily when hitching up/unhitching and it's not in a place where it can be accidentally activated.

Dutch Star Don · 03-26-2025, 01:14 PM

The Curt harness has two plugs for each side. It only takes a moment to plug both sides in. There is a white wire near the plugs that needs to be connected to ground. Either loosen a bolt and slide white wire under it or use a self-tapping screw. I sanded a thin piece of metal that the wire could reach, used a self-tapping screw and then painted over it.

For some reason on mine, Curt set up the wiring so that it would run down the driver side, which typically has more obstacles to get around. Whenever I do wiring like this, I use the smallest split wrap plastic wire covering to encase the wires as I run them forward.

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BJ6 · 04-01-2025, 07:15 PM

Might want check wit Blue Ox on whether the 2024 Base Plate works on the 2025. The grill changed. Last I checked, Blue Ox didn’t have a Base Plate. Just got my 2025 Tahoe Base Plate installed at Roadmaster last week.

NCRog · 04-06-2025, 06:13 AM

Yes, you're right, Blue Ox changed the baseplate for the 2025 MY Yukon, to address the grille change. The Denali/Adaptive Cruise Control PN went from a BX1745 to a BX1766. When I first started looking at '25 Yukons the Blue Ox website didn't list anything, told you to call them for details. It's now on the website, together with a complete set of installation photos and instructions. I did a DIY installation, went on without a hitch (pun intended!).

That's a pretty robust hunk of hardware, it weighs 32lb ... my 2019 Yukon kit was two separate baseplates, no interconnecting piece. I think the problem with the earlier model was there was no way to get around the cruise control and airbag units and they figured the chassis rails were tough enough.