Rear parking sensors not working

[downthedrain]

Hi,

I have a 2009 Mk5 Golf 2.0Tdi, I bought it second hand so I believe the parking sensors are original but not 100%.
Recently they had been constantly beeping when I had the trailer connected (flat connector) whereas it didnt before. Then last week they stopped working altogether.
I have done a bit of googling and read that this has happened with people's Mk6 after getting a new battery or being jump started, I did have to get a jump start around Christmas time and it was some time after that that they started beeping constantly with trailer attached but I am not totally sure on the exact dates.
They said that they replaced the parking sensor control unit and it was all ok again, so does this seem like the problem and if so where is the rear parking sensor control unit?

Thanks

[JustCruisn]

When I have bikes on the back of mine the buzzer is constant tone. Next time reverse is engaged (without restarting) it does not beep at all.
Once the bikes are removed and restarted it works again.

I would imagine the trailer would have the same behaviour. If still not working after a restart then get a VCDS scan.

[downthedrain]

yeah they havent been working for over a week now without the trailer on