Turn signals cause instrument panel to flash
 

I have a 1991 300 SL. 43,000 actual miles. I love this car! Recently, on occasion, not every time, when I activate the turn signal lever all of the dash lights, gauges, etc flash. The fuel gauge, the oil pressure - everything seems to cut off and on. The entire incident is a split secong in time. What's happening and how do I fix it?
Thanks!

Mother board issues are common on that instrument cluster.

Either a COMPLETE new one from dealer OR a repair from "Beckmann" would be the best way to go.

Instrument cluster circuit board repairs are not for the basic DIY or the meek at heart. I would consider Beckman for repair or at the least, look for a used one for a swap, even though it could easily have the same issue. The MB ciruit boards can get very touchy and the solder joints get brittle with age despite milage on the car. Good Luck