Your turn signal switch may be "fixable" if it is like mine. Carefully remove it, a couple of screws under the rubber cover, and look it over as you move the lever. Careful, don't drop a screw into the column!!

You should see that a pair rollers inside the assembly, top part and bottom part of assembly, move slightly into small grooves in the case, depending on whether you are signalling a left or right turn. The groove acts as the detent to hold the switch on as you turn the wheel. This groove wears slightly and its sharp edges are rounded off, which allows the lever to pop out of the detent groove. Take a small jeweler's file and slightly file the groove of the problem direction just a hair deeper and sharpen up its sides, but not too much or it will not cancel when the wheel swings back straight ahead.

Clean off any small filing debris and dab on a tiny amount of white grease to smoothe the roller action. Just a little, don't foul the works with grease. Re-attach the assembly and give it a try. You should have just saved yourself $150.

I did this on my 230/8 about twenty years ago and have not had to repeat it since. I plan to service my 350SL the same way this summer, same switch, just harder to get at.

230/8