Nissan qashqai towbar fuse blown

Hildy Couzens

We had a 13 pin tow bar fitted last year which has worked ok until now after hitching to the car the indicator lights failed, we then unhitched and the car would not start. An RAC check revealed 2 fuses blown in the towbar wiring adjacent to the battery
(battery was not flat) our car is qahquai +2 2010 and the van is a sprite major 4 2012, does anyone know the possible cause for this.