E39 (2001 525i) On Board Computer (OBC) does not cycle thru functions when BC tip of turn signal stalk level is depressed. It stays stuck on displaying only the outside temperature (B21 / X770). I couldn't find anything in TIS online forum, and my Bentley manuals don't shed much light on troubleshooting (Vol. II, ELE-441 to ELE-445 seem to apply). Any thoughts on what to try next? I suspect it's not a lamp/bulb for fuse problem, because the Temperature display on the instrument console is fine and correctly sensed. The radio works fine, so no onboard monitor impact there. Is there a way to check the BC mode function switch? - Thanks for any help, Paul
If you can find wiring and connection diagrams, I presume you could use a multimeter - don't know how much of a challenge removing the lower steering column cover would be; if security bolts are involved, it could be a hassle. I suspect BMW would make the cover removable so access for replacing turn signal stalks, etc. is easier. There may be other options, but I don't know what they'd be, I'm not an E39 expert!