Reversing lights - help!

The reversing lights on my car (a 1990 GTI Cabriolet, DX engine) haven't been coming on. I checked the bulbs and they are fine. I checked the fusebox and the fuse for the reversing lights had blown, so I replaced it. The lights still weren't coming on. So I checked the fusebox again and the fuse had blown again.

It has had a 10A fuse in there. First off, is that the correct one? If it is, what else might be causing the problem? I had the clutch replaced last week and some welding done to the bulkhead after the clutch cable pulled through, so might that have had an effect? I really need to sort this asap as the car's MOT runs out this week.

Any suggestions?

Thanks!

 

Could be wires trapped on gearbox mount
Or could just be the 2 pin switch since they metal
Yes 10amp fuse is fine in there
Rev lights does not come under a mot so if don't get fixed in time don't worry

unplug the switch see if it still does it, and as above chase the wiring see if its shorted anywhere

Got this sorted - the switch was shorting out. We put a new one in and now everything is working as it should.

Thanks for the help!