Also I learned about a common way for Mercedes to operate turn signals where one direction is just a direct signal and the other direction uses the same wire but the signal goes through a resistor, really weird system. The 140 I worked on would blink the same way no matter which way the signal was operated, again due to this loose screw.

If this really ties in with the crank signal I'm not sure but worth looking at the wiring diagram. I can see that this might be a problem only when it's hot.

as long as I keep windows down no problem,or air condition