2018 Chevy Tahoe

I have the same problem with my 2019 Ford Fusion Energi. Just wired in a 12V fused outlet from the car battery & positioned it next to the steering column. Works great with my Brake Buddy. On a long multi day trip just have to run the engine daily to make sure the battery doesn't run down. Never had a problem on a single day trip.

I brought a hot wire from the coach through the firewall to 12V outlet for my RVI II.

Thank you

The Tahoe likely has electric power steering.
The battery must be disconnected to avoid the Tahoe constantly trying to recenter the steering while towing. Doesn't matter if the key is off.
This will definately kill the battery and it will reportedly cause the Tahoe to wobble back and forth quite violently. I have heard that once it starts it goes back and forth and doesn't stop until you do. Heard it is super dangerous.
My Chevy has the same setup instruction. I in stalled a battery disconnect and ran a 2nd direct power line from the battery to power the brakebuddy.

it's likely to keep the battery from being discharged while in tow. if that's the case then your options are to...

- determine which accessories are live when the key is on but engine off and then pull those fuses before towing.

- hook up a charge line between your toad and motor home to keep the battery charged.