if you need mb tools read this
 

i you are looking for mb tools to do it your self check out this link

http://www.technictool.com/mercedes.htm

now if you are looking for a on/off ratio-tester good price check this link.

http://www.technictool.com/m0039%20m126-0521.htm

enjoy jose

ON/Off tester Very pricey
 

I just bought a DMM with Duty Cycle measurement for $40.00 at sears, it does almost the same thing.
By the way, does anyone happen to have the table for diagnostic
codes for a 1986 300E?
I find codes for models from 1992 onward, but no one seems to know for older models like mine.

PS. I know codes are not given as flashes or numbers, just as duty cycle readings. I would like to know what they mean.