My 2003 e39 540 has been great so far except for the "standard" issues, cooling system, leaky vapor barriers in rear doors, front thrust bushings, etc. I seem to have found another minor bug, the horn stayed on all by itself last week in DC traffic. I must say that it would have been really funny had it not been me . A simple removal of the fuse seems to have solved the problem, so i did not get shot in traffic, however no horn in DC could cost me some body work. But now i think it is either a short in the ground wire in the steering area or a bad relay. Any insight into this would help and a DIY on how to get to the ground wire in the wheel area and/or where the relay is would be great. The local dealer here was less then helpful when I went to check on the relay saying i would have to pull it for them to ID it and they did not know where it was . Thanks a bunch in advance.... Clarke
Horn Update Just to update on the 540 horn problem, in case any of you have a similar problem. When i removed the front of the steering wheel (buttons and plastic housing around the air bag, front of M wheel) by removing rear torx screws and releasing various tabs the problem became clear. The local dealer had replaced a faulty cruise switch under warranty. The dealer BMW tech had no idea what he was doing and had ripped the wheel cover off and broke many of the internals. Very sloppy job at "major" local DC BMW dealer! As part of this disaster at least two metal screws were flying around for quite some time in my wheel. These would get stuck under the horn ground and lock the horn on. Several problems I have had out of warranty on my 540 have been traced to bad dealer work, be careful when you get "free" repairs under warranty .
