I think I found the OVP, it is located just to the right of the brake booster on the 87 300SDL as you had said. It looks like a recangular box with a flat 10amp fuse housed horizontally at the top of the device. The fuse is still good. When I pull the OVP out, should the dash lights turn off or is there something else that I need to do? Thanks for all of your help.