Indicator audible warning

EdwardG

I have just bought a second hand Volvo XC60 and had Volvo fit a removable tow bar with single 13 pin electrics.However when the caravan is attached and the indicators are on there is no audible warning to let
me know that they are working. I have checked it out with Volvo who just looked blank, also contacted the Caravan Club technical help line. The response there was that it may be correct but the only way to tell is if the blink rate of the indicators increases
when a bulb is removed from the caravan.

To me this all seems very hit and miss and how would I know if the plug had fallen out?

Any ideas as to how the law stands on this?