Wet weather electrical gremlins

[Jacob100]

Recent wet spells have regularly messed with my windscreen wipers (on all the time), central locking and alarm (not working/going off all the time) and seatbelt sensors (on all the time). After a dry day all goes back to normal again. Is there an obvious place to start looking at?

 

[uHu]

Windscreen leak. Either because it was changed not using proper parts and method, or because of rust. All the water getting through the seal ends up on one or several ECUs or fuse/junction boxes under the dash.

That said, when I had a problem with the alarm going off, it was a small plug in the bottom left corner of the upper tailgate. The plug connects the door switch at the lock. This plug is wrapped in foam, soaks water, corrodes pins. Clean up, spray, remove foam: good for years.

 

[Jacob100]

The windscreen has not been changed and I've never picked up on any rust around it but will go over it tomorrow. The wipers have occasionally come on when I've gone through deep puddles. I can deal with them going off for 20 minutes or the seatbelt light flashing but coming out in the morning and the fob not working and setting off the alarm is v annoying.