2Q's: front demister and illumination steeringwheel buttons

So, I think I vaguely remember the steeringwheel buttons being illuminated, or am I wrong? It's really hard to find the right buttons in the dark right now. I haven't checked fuses yet, just wanted to make sure the buttons are supposed to be illuminated before yanking all fuses out (and knowing me: wrecking something unrelated...).
Since I don't remember for sure if they were ever illuminated, I don't know if they STOPPED being illuminated when disabling the stock radio and putting an aftermarket one in the pocket below it...

Second question: the front windscreen demister (one of the buttons I regularly need) seems to decide for itself when and if it operates. The symbol lights up, but the fan does not kick in half the time. If I have a fogged up front window, I want it to blow like a 25$ hooker, and not to force me to go into the climate menu and select the blow-at-my-feet-and-front-window-button and manually turn up the fanspeed to max...

Is this supposed to have a mind of its own? And if not, any clue what is wrong? And if it IS normal: anyone want to buy a Prius before I run it into a ditch? (Hopefully the anti-misting spray I bought will prevent me from actually loosing my temper, but it is seriously testing my self restraint...)

 

Thanks John, so it does have, kind of, a mind of its own. I don't agree with Toyota's choice of doing it like this, for even cold/somewhat-moist-air will, imho, be better than hardly any airflow at all to demist a window, but at least I know it is not malfunctioning.

As for the illumination, I will try to look up the plugs and its separate connectors for the stock radio, to see if that caused it. There are many people who replaced their stock radio, and I cannot recall ever having read other people running into this issue. I did not buy any wiring harnass, as there had already been installed a carkit which converted the Toyota wiring into an ISO loom. Thanks for your input salguod!

 

So any clue as to where the current limiting resistor is? Or where it gets its power from? I have just found some threads about the clock-spring being messed up by the steeringwheel-recall. All buttons function properly (although I am no longer using the radiobuttons, so not sure on their functionality). So that is still a possibly cause too, depending on how it is wired up exactly.

 

I'm looking at the 2006 tech. document and found some info on the C12 Combination SW. It seems to have all steeringwheel buttons. The illumination is in page 177 (no resistor values) and page 433. It goes to the rheostat R7. I am not clear enough (its late...) to figure out what connector that goes to.

It might be the same illumination rheostat wire in this plug. (pin 13.1). But all other illumination is working fine, and so is the rest of the MFD.
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