It has been raining a lot for the last weeks in Berlin. I was eager to install the solar panels. So I drove around to find a bridge that offers a dry place to work on the roof. While driving in the rain I realized that the wipers moved very slowly.
I couldn’t find any issues with the wipers or the motor. However, I also observed that the blinkers were flashing a bit weak. While diving deeper into the issue I realized that several electric devices operated weakly:
- the headlights
- the blinkers
- the wipers
- the fan for the heating
- several lamps on the instrument panel
Hmm, where should I start looking for the root of all these problems? 
With the help of the wire diagram I tracked the issue down to the fuse box.
All fuses seemed intact however some connectors looked really bad:
Some cables even looked scorched:
On some of these connectors I measured a resistance above 200 Ω. 
The connectors were held together by bolts that got loose over time. These loose connections caused very bad conductivity, resulting in a lot of heat which further led to corrosion. A vicious circle!
Ignoring this issue might have resulted in my van going up in flames. 
All shops I checked were out of stock (part number A0015450001) so I sanded all the connectors,
replaced the loose bolts with proper screws and linked the connectors with a thick copper sheet.
Before installing the fuse box back into the van I measured the resistance of every single fuse connection:
All connections below 1 Ω. Yay, another fixed issue! 
Installing the solar panels will hopefully the next project! 