Inside the button row

[roket]

i had enough of the mystery of how that row of buttons worked, so i once again put a part of my car at risk for the greater good. i can definitely say that i did not expect this result

back of the buttons, with a strange 8-pin ribbon cable coming out of the pony button, which hooks to the back of the PCB. note how every button has a spot for a lens for that amber LED the "max defrost" has, and i assume that the "auto start stop" button has on vehicles with that.

here is the back of the PCB. there is the connector for that ribbon cable, as well has the ten pin headers for the connector to the button cluster. nothing super remarkable on this side

now this is the interesting part. somehow, that row of 6 buttons only has one actual button-like switch on it, and the row only has one actual point of contact and moves as one. i suspect that ribbon cable from earlier is some sort of capacitive sensor, so it can use that info along with the fact the circuit was completed to determine what button was pressed. one thing of note is the LEDs. even without auto start stop, the LED to light up the "off" text is still there, see the upper white rectangle with the amber center. similar thing for the backlighting, every button has it, even the unused one. there also looks to be places for all of the other buttons to have the amber LED added on too. another noteworthy thing is that rotated integrated circuit on top. i need to go back and look again, but from what i can tell, that is a Microchip IC of some kind, with 48 pins in a QFP package

what this all says so far is that, unfortunately, those without auto start stop cannot reasonably repurpose the blank button. if i find more info on that IC or the little one in the middle, i will update in a reply

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[roket]

update: i was able to find out that the integrated circuit is in fact from Microchip and is the PIC18F56Q43. the little rectangle IC is from NPX and is the TJA1128E

 

[Alan Applegate]

I suspect if we knew the number of PICs used in a Mustang, we might be surprised. In fact, the last time I was looking for one to fill a design niche, there were over 100 listings of them. No surprise!

 

[SmoothButter]

I really hope a 3rd party can make a higher quality replacement for that piece, it feels so cheap

 

[OutofNowhere]

Interesting! I was just thinking the other day how weird this row of buttons is, with how it feels when you press a button, because it feels like you're pressing the entire faceplate in. Now I understand why! What a bizarre construction. I suppose it was cheaper to do it this way rather than actual separate buttons?

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