Golf 4 Interior Mirror Disassembly

"I have this great rearview mirror with a rain sensor and automatic dimming. I want to disassemble the mirror housing to install a switch (to disable the automatic dimming). Before I start breaking things, I was wondering if anyone has disassembled a similar housing before, or knows how it's done."
Is the casing clipped on, or is the front frame glued? What's the best way to proceed so that nothing gets damaged?
I would be grateful for a few hints.

It would be easier to simply cut off the power supply at the plug, which is located near the interior light. I think the risk of causing damage is too high otherwise.

"That's certainly one way to completely disable the auto-dimming feature. However, I would prefer to install a switch (as is already available in newer models). While I like the auto-dimming feature, my girlfriend doesn't. If the front frame isn't glued in, it shouldn't be a problem to do that."

I believe I saw in my user manual that when the device is plugged in...
Reverse gear, automatic dimming disabled.

It might be easier to use this mechanism than to try to do anything with the mirror itself.
to be interrupted when opening.

Okay, what you said about the system shutting off when in reverse is generally correct. However, we now need to figure out where the signal is being tapped and trace the wiring (especially identifying its color). I personally think the idea of using a switch in the mirror is a bit more elegant.
It looks like it will probably end up being a self-experiment.

"If I'm not mistaken, a self-dimming mirror for a G4 costs around €140. So, it's best not to mess it up... With a service manual (SLP), it shouldn't be a problem to figure out where the connection to the gearbox is and which wire color is used."

Regards,
Guste.