when i got my e34 back in aug last year, i noticed that one of the fuses was melting, and that it was held in a separate 'holder', not in its normal slot in the fusebox. i got one electrician to put in into a proper fuse holder box in the hope that it will not melt. then later on, my aux fan died, and the mech said the ballast was busted, so he fixed a merc one, cos the bm ballast was not sold separately. I later found out that the merc ballast was better constructed in that it had a ceramic heat sink.
then, after a few months, the fan died again, and this time, the mech said had to change it. so, since i 'trusted' him, i paid 900 for it. well, it worked fine for a while.
then, after a few months again, the fan konked again. but i didnt realise it until i took it to the a/c guy to check, since the a/c didnt seem to be cold sometimes. well, he said there is some problem with the wiring, especially with the fuse that was in the holder. that fuse seemed too hot. so, he recommended another wireman to me.
fortunately for me, that wireman immediately found the problem. first of all, he said, the e34 tends to run really really hot in msia. and this meant that the aux fan had to work really hard. the original setup of the wiring and fuses couldnt cope with the extra load. so the fuse for the aux fan tends to melt. another problem he found with my car was that the previous owner had rewired the aux fan and a/c blower together, causing a double 'loop' (not sure what that means). this further caused the amperage to increase, thereby increasing the heat and meltdown of the fuses.
so, he fixed the wiring, used heavy duty wires and fuse holders, added three extra fuses, and also changed the temp sensor to a 85 deg from a merc (the bm one was 97deg). he also changed the ballast again to a merc one. there was no prob with the fan itself.
and now, my car runs cool, the clutch fan hardly kicks in, and i got more POWAH!
If possible, I'd like to put in a radiator as big as 535i's, that'll really cool things down...