MOT Failure - Towbar Electrics

[RoB5urf]

My 2017 T6 Beach failed its MOT on "Trailer electrical socket (13 pin) not operating the trailer lamps as intended". The towbar was factory fitted and we've never had an issue, and I always check the lights after attaching the bike rack.

Initially the garage suggested taking it to a towbar specialist to check but I'm sure they would just connect up a light board (they won't have the same VOSA approved tester that MOT garages use). In the end I returned to the garage with my bike rack and was able to show them that all lights were working perfectly. Begrudgingly they signed-off the MOT, although they probably shouldn't have! I'm planning to get this checked again well in advance of next year's MOT.

I've seen posts on other forums where other's have experienced something similar - just wondering if any Cali folk have too?

 

[WelshGas]

My 2017 T6 Beach failed its MOT on "Trailer electrical socket (13 pin) not operating the trailer lamps as intended". The towbar was factory fitted and we've never had an issue, and I always check the lights after attaching the bike rack.

Initially the garage suggested taking it to a towbar specialist to check but I'm sure they would just connect up a light board (they won't have the same VOSA approved tester that MOT garages use). In the end I returned to the garage with my bike rack and was able to show them that all lights were working perfectly. Begrudgingly they signed-off the MOT, although they probably shouldn't have! I'm planning to get this checked again well in advance of next year's MOT.

I've seen posts on other forums where other's have experienced something similar - just wondering if any Cali folk have too?

What exactly was the problem?

 

[RoB5urf]

Apparently the test machine indicated none of the lights were working via the socket. I was told another vehicle was fine when it was connected. There's a very long thread on one of the caravan forums where others have had a similar issue.

 

[pchmlk]

It sounds like the test equipment is to blame doesn’t it?

 

[WelshGas]

Apparently the test machine indicated none of the lights were working via the socket. I was told another vehicle was fine when it was connected. There's a very long thread on one of the caravan forums where others have had a similar issue.

There are numerous different types of electrical circuits to Towbar sockets.
On the California with factory fitted Towbar and electrics when plugging into the Towbar socket a microswitch is activated within the socket that tells the vehicle a Towbar is connected so the rear fog lights and Parking Sensors are disabled and the lighting circuits energised by the vehicle, also the rear brake compensator is adjusted, unlike the older analogue system where the towbar electrics were just wired into the rear light circuits.

 

[RoB5urf]

Thanks WG. Not sure what all that means but my takeaway is that not all cars are wired the same way so maybe certain types are prone to this type of issue. I'll get it checked out well before the next MOT.

 

[Roger Boeken]

towbar tester only 17euro on amazon, if it shows you are right take it with you to the MOT

 

[teeboy]

If it is the VW factory towbar - then I would remove it before the MOT and shove the electrics up behind the bumper...

 

[Roger Boeken]

If it is the VW factory towbar - then I would remove it before the MOT and shove the electrics up behind the bumper...

Will not work in Belgium at least: removable towbar must be in place during MOT, I was lucky they allowed me to mount it during MOT once.

 

[WelshGas]

For Information. MOT Testing Manual.