BMW motorcycle horn & hi/low beam switch repair

BMW motorcycle horn and hi/low beam switch repair

By Bob Fleischer, also known as snowbum

This switch was used on the /2 up through the /5.

Have any and all battery negative wires OFF the battery post FIRST.

The stock horn switch is a push-button that also doubles as the high/low beam switch.  The horn section of the switch is a contacting area around the very central barrel area inside, touched by part of the black push button (tiny metal disc).

The push-button has a metal shaft going into the switch area.  On that small round shaft is a C clip (or E-clip).  That little tiny Jesus Clip (you KNOW why it is called that ) will fly out across the garage, never to be seen again, after carefully prying it sideways off the shaft using a tiny jeweler’s screwdriver or similar small tool.  DO NOT lose it, and do NOT deform it by being ham-fisted.

Put a large old white bedsheet around the area to capture the flying clip .and the spring, etc.  Murphy’s laws say that the clip and spring will fly out OVER the bed sheet, and that they will never be found again .and that you will never figure out how the internal contact is refitted anyway.  With this, you will not have things flying if you are an old hand.  Remember, flown parts need to be eventually returned to rightful positions!

Be exceedingly careful about removing the clip. The push-button needs to be pressed INwards at the same time. I might be able to do it with my two hands (I do), but YOU might want to fashion a method of SECURELY keeping the push-button pressed inwards. Remember, this is all done while the outer switch is dangling from its wires after having been unscrewed from the bar switch holder.

Pressing the button will immediately show you what I am talking about as the C-clip moves right along with the shaft.

Under the push-button is a brass-looking funny, irregular, and bent-up piece of metal that is the contact(s) for the lights portion. That will come out, and you will spend a lot of time figuring out how it fits when you replace it UNLESS you remove the E-clip carefully, button pressed-in (some), and very SLOWLY remove the push-button, NOTING the exact position and method the brass rotating part fits. Take a photo as that might help you remember.

Be sure to note which side is up and the orientation.

There is a SPRING under the push-button cap.  It is light and thin and easy to lose.

When into the switch, clean all contacts with some solvent, dry them, burnish all contact parts with a good pencil eraser, and use a faint smear of silicon grease on the contacts when reassembling.  This makes it especially fun with slippery fingers to get the spring and C-clip and internal wiper parts back together without much cussing.

Edited by Grammarly, 11 July 2022