I have attempted to install a bypass relay for a towbar. When I connected it up the reversing sensors went nuts. I have disconnected it but the rear fog light will not work and I get a warning light for a blown bulb. No current is being supplied to the bulb. I suspect that I may have fried a relay. Any suggestions as to where this might be located or as to what the problem might be?

If you suspect a relay is fried, I believe they are all in the fuse box or under the bonnet near the battery.

Ian