Mercedes sure does not make it easy to tow with their premium priced large SUV

I bought a Bri-Mar trailer last week, equipped with electric brakes & LED lighting. In preparation, I had ordered a Tekonsha Prodigy RF Trailer Brake Controller # 90250, a unit that received good reviews from other GL owners.

The advantage of this unit is a wireless radio control, which supposedly does not require any drilling, splicing, or modification of any type. This sounded great, as the vehicle is leased.

So on Sat, I drove to pick up the trailer, with all the componants & a few tools which with to mount the unit onto the trailer.

First failure was the inability to pair the trailer mounted power box to the vehicle remote, which plugs into any 12 v lighter outlet. Hence, no powered brakes.

The second failure was the trailer lights. They came on, but only in a constantly flashing mode. I did get brake & turn lamps, but with the other flashing lamps all over the place, I decided driving the thing 50 miles home would be pretty stupid.

Research has educated me that MB, as well as Volvo, Audi, Porsche, & VW all have problems properly working with trailers equipped with LED lighting.
One maunfacturer, Valley, offers an adapter that has some resisters that trick these "oh so smart" german cars into believing that normal incandescent lamps are on the tow vehicle. Guess what. No one has the unit in stock, and the manufacturer will not have more until mid June.
Meanwhile, here I am stuck with a trailer I can't use because my $60K POS German engineered "tow vehicle" is too fricking smart.

Do I sound pissed? That's because I am.

I've yet to call the MB stealership to see if they can offer a solution.

I've tested the leads on the factory 7 prong trailer wire receptacle.
Lead #4 (12v battery power) is indeed live when the engine is started.
Leads 5 & 6 are energized when the brakes are applied, and flash when the corresponding turn signal is switched on.
Lead 1 is a good ground.
Lead #2 is NOT energized. Please correct me if I'm wrong, but I understand lead 2 to be the varying output brake lead used on a conventional harness mounted brake controller, and as such it is acting normally, as no controller is installed. (?)

Any light anyone can shed on this situation would be greatly appreciated.

David in MD