wipers work on full speed only,sunroof & elect windows inop on 1990 BMW 735i

in our college workshop we have a 1990 bmw 735i(the all singing all dancing fly by wire type)the wipers will only work on full speed and the sunroof and all 4 electric windows are inop, i have carried out checks on the earth points although i have yet to find the g200 one on the left of the steering column.can any kind soul assist me as i have volunteered to help out a colleage to prevent an otherwise nice car going to the scrapyard.

Asked by for the 1990 BMW 735i
Hi there. The solution to the problem is simple. Remove the rear seat and in the fuse and relay block located on the left hand side is 2 relays (the general module and power module) Remove these two modules and re-insert them. If the problem hasn't been solved, replace the general module ( the module with the white and black plugs underneath them)
thanks will try
2 more answers , 1 more comment
Any progress on this? Did you have it checked out?
sadly no, we cannot get access to a sufficiently accurate wiring diagram so that we can follow the power flow & carry out continuity tests
dude donwload the maunual ..and type haynes bmw and download it for free instead of buying it ...