i have a 1992 mercedes benz 300 e when i turn my lights on it blows the fuse that controls my left running light and my left head light dose not work either any ideas.

sure, the wiring is grounding out somewhere, DO NOT JUST USE A BIGGER FUSE, OR JUMP IT OUT., however finding electrical issues takes time and patience. check to see what else is on that fuse,, other lights, and such. begin to check at the connectors, to the bulbs, making sure they appear not to be pinched, and connect, reconnect correctly for corrosion. Once you check every bulb, and each connector to them, and find no faults, (will the high beam work at all on the left)? let me know if you came across a bad connection, or what else is on the fuse, so i can help determine potential electrical issues.

i have checked as much as i could find with the wiring and it seems to have good connections the fuse that keeps blowing is marked #8 in the fuse box it says that it only runs the running light. but my head light does not work as well do you think that it could be a bad switch that turns the lights on. ?

unplug the light that does not work and see if the fuse does not blow. It could be shorted instead of a bad bulb. if the fuse still blows with the light unplugged it is something else try that first