my tail light cluster had some very worn connections so I recrimped a couple of spade terminals but since connecting them I have no tail or front parking light. I did blow a fuse by whirring a wire have I blown the bulb monitoring unit?

That's a bit odd Will. Check fuse no.2. It's fed directly from the ignition switch so I'm guessing that it provides the power to the BMU as a whole via the parking light wire (grey/white). The tail (grey/black), the parking light (grey/white) and the brake light (grey/yellow) are all on separate circuits in the BMU. Do you still have a brake light?

I'd love to know what BMW's designers were thinking (or smoking) when they came up with the wiring layout. It could have been seriously simplified and still provided the same functionality.

good luck will

yes check the fuses first

A clean up of the terminals in the fuse holder did the trick guys, thanks. I thought just shoving the fuse in and out might do it but it took a bit more. might replace the unit to be safe long term.

88KE wrote:A clean up of the terminals in the fuse holder did the trick guys, thanks. I thought just shoving the fuse in and out might do it but it took a bit more. might replace the unit to be safe long term.

How'd you clean the terminals? I think I may have the same problem on a long-sitting 1985 K100. None of the switches in the right and left switch gear seems to work, except the starter button. Flashers work when the emergency switch is thrown, brake lights work.  Fuel pump works. Nothing else.

lots of posts in here about those items tiolli

have you found the search feature yet ?!



I would be starting under the tank where all the hand control cables terminate into the electrical connectors ...often found to be corroded and in need of help

deoxit works well

cheers

Tioli wrote:

88KE wrote:A clean up of the terminals in the fuse holder did the trick guys, thanks. I thought just shoving the fuse in and out might do it but it took a bit more. might replace the unit to be safe long term.

How'd you clean the terminals? I think I may have the same problem on a long-sitting 1985 K100. None of the switches in the right and left switch gear seems to work, except the starter button. Flashers work when the emergency switch is thrown, brake lights work.  Fuel pump works. Nothing else.

Tioli,

The left & right switch gear do suffer if not used regularly. Corrosion/oxidisation products do build up on the switch contacts over time and eventually will prevent a good electrical connection so that they don't work.

It is a little fiddly, but actually a pretty easy job to strip the switches down and clean up the contacts with fine emery paper and electrical contact cleaner (deoxIT). As Charlie says, there are lots of posts on this issue - you should read these first, especially the one that tells you to dismantle the switch in a shoe box or plastic bag to catch the pesky spring loaded ball bearings etc. When I first joined the forum, I admit to laughing out loud as I read this advice - having just spent the previous hour searching my garage floor for all the small bits that had sprung free when I opened the switch. Hindsight is a wonderful thing, but I learnt my lesson and now always read the advice first....before starting the work!