E90 electrical issue

[//M SPORT]

Hi chaps.

My e90 335i had a strange issue. The hooter, electric mirrors and pdc work intermittently. All of these don’t work together and then perfectly fine for a few days until it does not work again. Seems like a loose negative?

I checked every single fuse, and can’t find the issue. I also checked all negative cables in the sides of the bonnet, nothing there.

Any help with how to better diagnose would be appreciated.

 

[Solo Man]

I once had a very long problem (meaning it was going on for a long time) with the lights dimming when idling and eventually traced it to a bad earth connection in the boot of my X5. Earth bolt was ever so slightly loose. Could fasten it about one to two full turns! That solved the problem.