I have a towbar on my 2019 X3 got it fitted just after I got the car in February 2019. I had no problems with the rear sensors until recently and when I have my trailer or caravan on the back and go to reverse the brakes come on and you cannot override the sensors like before when I first got towbar fitted, also when you try to reverse onto a slight incline on the ground it does the same the brake automatically comes on 

You could reverse no problem before it is just recently this has happened .

Any help appreciated 

Thanks John

Hi John

Welcome to the Forum

It seems you need the Towbar electric pack tested or changed by whoever fitted it. I take it your trailer brakes are being applied ?

In the UK normally the rear parking sensors are disabled when the trailer electrics are plugged in. I do know that trailers over a certain weight in the US have electronic brake assist is that your issue

Dave

Hi Greydog

Thanks for your reply 

It is the car brakes that come on when I reverse with the caravan or trailer ,they also come on when I try to reverse onto a small incline in a driveway 

thanks 

John

Hi John

If you have the Auto H button below the Parking brake if you haven't activated it then I think you have a definite issue with the auto hold system on your car. It is supposed to help when pulling away on hills etc it shouldn't be affected by the fitting of a towbar. Talk to your Dealer they should be able to carry out a diagnostic check, 

Dave