yes the fuse was replace and it was good from before.

Ok..you may want to also verify that the OVP is not the original one b/c they were famous for electical gremlins and any old one should be replaced , regardess of it's present condition... Benz finally upgraded the part. Take the old one out , look at the part# on the side..if it is 000-540-52-45, change it . The replacement is 000-540-67-45, which in all probability that is what you will find in there now.......
Before taking it out , give it a few taps and see if that ce comes on KOEO, just for kicks. Could have a bad connection at the base.
I very much doubt you have the original OVP b/c none of them lasted this long, but it only takes a min to check and no matter what, you do not want the old style OVP in your car, for sure....even if it has nothing to do with your present probs