G3: Mysterious Security & Vacuum Issues

Hello everyone,

After unsuccessful attempts to find a solution, I now have to describe my problem. I must mention that I am still in the learning phase regarding autofocus (AF), as I have mostly used a 1Z setting so far.
After a funny incident involving damage caused by a weasel, I had to "reinvent" some parts of the hose system. I think I got everything right, but please correct me if I'm wrong.
Okay, so: A hose is disconnected from the pipe leading to the coolant reservoir. I suspect that's where the boost pressure is tapped, and I've connected the end that protrudes from the center of the reservoir to it.
Then, the little creature bit through a vacuum hose. One end was protruding from the splash guard between the two coolant hoses that lead into the interior to the heat exchanger. I reconnected it, and so far, everything seems to be working properly again.
"General question for understanding: What is the purpose of the negative pressure inside? Is it required by the Climatronic system?"
I also found a faulty fuse strip located below the coolant reservoir, under a transparent cover. Behind it, in the same housing, is a 20A blade fuse. I can't assign either of them to a specific function, as everything seems to be working. It's not related to the glow plugs or the coolant heater.
Unfortunately, I can no longer see the value of the strip fuse.
I would be very grateful if someone could help me.

Hello snowman,

The vacuum hose on the injection molding machine is connected to the vacuum sensor for the recirculation flap.

I'm not sure which component this fuse protects (fan / coolant?).

"In vehicles equipped with air conditioning, this coolant fan control unit is installed and, according to the wiring diagram, is equipped with a 20A and a 30A fuse."

Regards,
Guste.

Thank you very much for your quick responses.
Okay, I replaced the fuse, and it turns out it was related to the radiator fan. The fuse probably blew because there was a bent, about 20 cm long piece of plastic jammed in the fan blades, which definitely doesn't belong to my car. Maybe my little furry friend brought it along to trade for the vacuum hoses...

Thank you both again for the quick responses.

Have I already mentioned that this is a really great forum?