Recently had a galvinised chassis fitted and have now been running the defender 90 300tdi for about 8 months since rebuild. This week the side light and tail light on the left stop working. The fuse has blowen replaced fuse and bulb no luck. No other problems with electrics and the brake light is working as well. Also when u turn the lights on without the engine running the lights are fine. When u start the engine the fuse blows any ideas