Mercedes® Overload Protection Relay, 1973-1981

The overload protection relay protects your car's expensive electronics from voltage spikes or any over-voltage situations. When the protection relay goes bad, some of the symptoms are rough running, tach/speedo not working, ABS light comes on, warning lights on the dash light up, etc. depending upon year and model. Always check the fuse on the protection relay and replace it if bad before you replace the relay itself.