check engine light is on. on 1992 Mercedes-Benz 500SEL

Check engine warning light is on. Is there any way I can reset this? What should I be checking? It's been on for over a year now.

I replaced fan belt and there's a squicking sound in the mornig but when the engine is cold, but it goes away after I have driven for about 1/2 of a mile.

Asked by for the 1992 Mercedes-Benz 500SEL
There is going to be a diagnostic trouble code(s) stored in the engine control module, you'll need to retrieve these and diagnose accordingly. However, since it has been on for so long, I would write down the stored codes and erase them, drive the car and see if any return.
2 answers
could be that ur belt is just wet, fanbelts do make sound if there wet esp in mornings