Hi Guys,
I've just today solved the problem of the RH electric windows, central locking, sunroof and interior lights not working.... After having replaced the General Module, Drivers Door Module and Relay Module,and changing both batteries, none of which worked, I came to the conclusion that maybe I was looking in the wrong area....I'm a slow learner!
With kind guidance from another E31 owner, usuing his car as a "guinea pig" we came to the conclusion that problem was associated around the 7.5 amp on the LH side of the the boot (row nearest the boot firewal, bottom fuse). After replacing, cleaning etc, etc that fuse and contacts; no change!.
I then had the idea to trace the wire that is fed from that fuse, and within about 30 seconds, pushed up, out of view behind the craddle where the jack base sits, was an in-line fuse holder containing a blown 7.5amp BMW blade fuse. Replaced it and Eureka, everything back in action!!
I don't know if this fuse/holder is standard factory fit, or is maybe just perculiar to UK cars. It certainly doesn't look like an aftermarket piece of equipment, and there's nothing else being fed from it, so I suspect its an extra failsafe device.
Having spent nearly £250 on used modules and new batteries, when the cause was just a simple fuse costing a few pence, my feeling are a bit mixed, but at least I'm more familiar with the car, and someone else might benefit from my experience!
By the way, if anybody's interested I now have perfectly good (spare) General Module, Relay Module and Drivers Door Module.
Hope someone else can benefit from this in the future. Also, would be interested to know if any other E31 owners have this fuse fitted to their cars.
Mark.