Self-leveling Susp problem caused by towing?

[Ranger]

I occasionally tow 4500lbs with my '03 4.4. My self-leveling suspension is now acting up where one of the front wheels is pushed down 20mm or so. Is at the local dealer the 2nd time in a month for this. The first time they "recalibrated" the suspension. This time they are not sure what the problem is, but they want to blame my Prodigy brake controller, which is rediculous. But how can I convince them that blaming the brake controller is absurd?

It's worth noting that I've not towed since they "recalibrated" the suspension. So whatever was the immediate cause of this reoccurance of the problem, it wasn't towing.

The Prodigy brake controller is the recommended brake controller by most experienced X5 tow-ers. And BMW makes no specific recommendation for brake controller, at least as far as I've ever found. All the darn thing does is connect to a brake light wire or something.

So, how do I address this with the dealer?

[Ranger]

Update. The dealer had the "North American Engineer", whoever that is, spend several hours with it yesterday. The official answer is that they wash their hands of if. Either the Tekonsha Prodigy brake controller is at fault, or it's wiring is at fault.

Of course all the controller does is sense the brake lights going on. I called Tekonsha and they burst out laughing.

[zerochief]

Good luck with all that Ranger. It seems most BMW dealers hate dealing with air suspension problems on X5's - I've been put through the ringer before as well. Is your X under warranty? If not find a good Indy with a GT1 tester.