Hello municipality, my 166 apparently has a mass problem. An acquaintance is an electrician (not a car) and we would like to know if the autoelectric can take damage with a 500 volt measurement. At 500 V the voltage overruns and you can determine where the error is. How else do you look for the error? Interestingly, if I plug the bulb in the back, it glows for exactly 4 seconds, then it goes out and later the filament starts to glimmer periodically and then again again. I forgot to mention that my rear part is except for brake lights without lighting. No reversing lights, fog lights etc. The other bulb does not react to the insertion of the one bulb. Light control unit I switched, missing! Who can tell me where the lighting at the back decreases mass? Thank you already, Christian