I replaced OEM radio (8701A495) and hands-free module (8785A052) with Alpine UTE-92BT unit. Everything works fine (even SWC!), although I am not sure about dimmer function. Seem that new radio is illuminated with the same level independently of daylight/night.

In short, my questions are: what to do with ILL- wire? Is it ground or not? Maybe I should use ILL- instead of ILL+?

In details:
All normal (=aftermarket, with ISO connector, not OEM) radios have ILL+ (illumination) input for dimmer function. The OEM has both, ILL+ and ILL- as shown in the left picture (OEM connector) below:

OEM vs ISO connectors

I made an adapter with following wiring:

connection table


As you can see, there is no negative polarity for ILL- on ISO side. Maybe illumination is coded as digital signal like CAN bus? Any ideas?

BTW, the final adapter with Alpine wire-harness:

OEM-to-ISO adapter with Alpine harness

 

It turned out that default illumination settings in Alpine radio were too bright (or maybe constantly dark and depressing Swedish weather is to blame).
After re-adjusting the brightness settings I was able to notice automatic dimming. So, "ILL-" connection seem to be not needed, all works fine! ;-)

Alpine UTE-92BT (before re-adjusting too bright illumination of the front panel)

 

A wonderful place for the microphone and communication via Bluetooth. The mic came with UTE-92BT unit. The dummy plug needs a little hole for it


Microphone.

 

Today, I have finally disassembled and cleaned up remote buttons sitting on the left side of the steering wheel. The resistors net with buttons has a tendency to change its resistance due to dirt and particles trapped between the circuit board and button contacts. I was surprised that buttons are not carbon-coated rubber but have real gold-plated pads. That's why it worked for almost 10 years, thank you Mitsubishi for that!

At first, there was a little hassle to unmount the buttons panel with a fear of accidental activation of the air bag.
Then, when I opened this panel and cleaned it up, I found an interesting fact: there is a support for additional button which is not present on the front side of the panel! See picture below.



In the electrical circuit diagrams there is no such button either. But well, my non-EOM stereo can learn new buttons, so I will try to find and order new panel with such button. For example, in the following picture (found among AliExpress products) there is such panel with an extra button. The only question is, what does that icon on the button means? (a cup of coffee, really?) Anyway, for me, that would not matter, I just need to find such panel which matches my grayed edge style panels (not black plastic). On the other hand the front panel with buttons is detachable, so black trim does not matter much and I can order this one anyway I guess.