My 97 R started throwing a fast turn signal last week. So I looked at the driver's rear bulb (front bulbs are working fine) and the bulb looked fine. I swapped the right and left bulbs in the rear and confirmed that the bulb is ok. After messing around a bit more, the blinker started working, so it seemed like there's a loose wire/bad connection.

A week later, I've got the same problem. I broke out my multi-meter, and though I'm mostly dangerous with electricty, I confirmed that there is power coming into the socket, as the needle on the multi meter jumped with each click.

So, it seems like there is power at the socket. The bulb is ok. But the bulb won't blink (or do hazards for that matter).

What to do??

 

I talke to my brother, the engineer with German cars. He suggested scuffing the contact points with sandpaper in case there was some gunk blocking the connection. Sure enough this worked. Problem solved.

 

a bad socket will give you the fast blinker thing as well