This applies to the dash switches used in K75s, K100s, K1100s and a few R bikes of the same era. I posted it at the K1100 forum and thought I’d post if here too in case it might be of use to someone.
Have your switches lost their spark? Do they not respond to your loving touch as they once used to? Do they feel all sticky and worn out? Have they lost the connection they had when you and your bike began your relationship?
Well, you have two options:
1) Throw away money at your local BMW stealership
2) Subject them to Dr. Duck’s Switch Rehabilitation Clinic where they can be cured by undergoing our simple 12 step program.
Step 1) Admit that your switch has a problem.
Step 2) Remove the switch from it’s slot. With a little wiggling you can usually pull them out from the front although sometimes they need to be pushed out form the back. When you see the pictures below you’ll get an idea of the prongs on the top and bottom that hold them in.
Step 2) Disconnect the switch from the wiring harness. I usually do the rehab in situ on the bike but there are tiny bits to lose so I’d recommend doing this on a workbench your first time out.
Step 3) Using a small screwdriver on each side pry the top part of the switch off. It pivots on a couple of nylon nipples. You need to pop both sides at once which is why you need two screwdrivers.
This is the step where you can lose tiny bits. In the rocker is a little tube holding a spring and a little part at the end which, when translated into English by German engineers, is called the little hollow phallus.
(Optional) If the graphic insert on the switch is worn (because you’re a wimp and use your heated grips all of the time) you can push it out from the inside. A replacement can be had from BMW for about $4-5. They just pop right back in and make the switch look brand new again.
Step 4) From the side pry the back off of the switch. For some reason it seems to go easier if you do it on the side with the wire termnials. Now you see the little slider inside and understand how the switch works.
Step 5) Clean the contacts on the slider and the back of the switch. I usually just scrape them with one of my little screwdrivers until I see shiny copper.
Step 6) Clean/lubricate the switch. Soak a Q-tiip in WD-40. Clean out the inside of the switch where the slider goes and the sides of the slider.
Also do the upper outside of the switch body and the inside of the rocker.
Step 7) Check the wiriing. If a few strands of the wire have broken or it’s broken altogether then it’s time to get the soldering iron out.
Step 8) Melt the solder on the terminal and remove the old wire. When you melt the solder clean out the hole it in with a tack or needle to make room for the wire to pass through.
Step 9) Cut the old end of the wire off and strip about 1/4 inch. Then put it through the hole and resolder it.
Step 10) Put the slider in and snap the back on.
Step 11) Put the rocker back on. Before you do this use a pen or something to get the slider in a halfway position. Put the rocker on it’s back (otherwise the little hollow phallus will escape) and push the switch straight into it.
Step 12) Reinstall the switch.