did you check for a broken wire loom from rear to chassis? Especially the touring has such probs.
http://img220.imageshack.us/img220/4...chtorng9zv.jpg
As with the sedan, same happens with the Touring. From trunk to chassis.
this pic is after the outer sheath has been removed.
and here
1994 E34 520i Touring - boot hatch and rear wipe problem(FIXED)
and here you see right side and left side wire loom broken
E34 - My e34 Touring experience... | BavarianForums
same on E39
E39 Electrical Problems Traced to Trunk Lid Harness Wire Chafing (DIY Diagnostic) - Bimmerfest - BMW Forums