First to the foglights: easiest is a swop of the bulbs from right to left to see if the fault moves. From my experience with E32 some hints to check, but I am not sure if that is the same set-up on E34
This big round plug is on my E32 behind the bumper left side, it is for the foglights and the outside temp. sensor, oxidation occurs http://bmwe32.masscom.net/johan/OBC_temp/OBC_temp.html
Then I once had the wire melted just close to the connector of the foglight, bare wires, but that was my fault, because I installed 100W H1 bulbs.
Use for all connections contact cleaner / contact enhancer, I fixed in the past years some problems just with such spray, for example the aux fan was not running, the spades of both aux fan relays were oxidized, just sprayed the parts, problem solved.
I also sprayed all fuse sockets with contact enhancer.
As for the wear pad sensor wire I just can imagine that it is not correct installed, is that clip there for the wire as shown on the last pic? http://bmwe32.masscom.net/sean750/re...rBrakePads.htm