Alfa Romeo 4C Forums banner
21 - 37 of 37 Posts

·
Administrator
Joined
·
17,255 Posts
Good work!
Sorry it took me a while to see and approve the first version of this. Hope you could cut and paste, rather than type the whole thing again!

Adding to DIY sticky.
 

·
Administrator
Joined
·
17,255 Posts
Thanks for the great info. I had to reformat this to be able to follow.
Took JWA's lead and did this to the first post, which will be part of the DIY sticky index for future reference.

Thanks for your work on this!
 

·
Registered
Joined
·
866 Posts
Given the noise limits restrictions that are enforced on some tracks the unused switch would be nice to be used for a silence/unsilence exhaust valve...
 

·
Registered
Joined
·
7 Posts
Thanks for this info. Did anyone figure out the pinouts? I see it is 12pin out of the toggle switch assemblies but doesn't seem that the 3 unused pins get a voltage when I toggle the 2 unused buttons after I toggled them. I did measure about 10.5vdc on another pin when I turn on the a/c but the door lock and mirror heaters don't seem to set 12v anywhere. I need a better setup to get into these pins. Perhaps tomorrow when daylight is back.
 

·
Registered
Joined
·
75 Posts
Apparently since I can't leave well enough alone, I decided to follow in @sthein's footsteps. Although I did cheat a little bit. In doing some research I discovered that, like several other parts in our cars, Alfa dug into their parts bin from other vehicles for these switches. And in this case, they were lifted from the Giulietta. Knowing there was a much better chance of getting used Giulietta parts for cheaper than anything with a 4C label I went on the hunt and found a set in pristine condition in Australia. (The Giulietta never made it to North America, so...) Basically, I wanted to really know what I was getting myself into before potentially mucking up a working set of switches in my car. Having the spare set to practice with (and scavenge for parts) gave me the confidence to proceed.

Here is the inside of the set of switches.
118092


Having swapped out the "dead" blocks which don't move for working sliders, the next step was to work on the switches themselves. While I could have messed around with the existing wiring inside the board, I didn't really want to bother with trying to reverse engineer the board or the pinouts on the connector. So as others have done, I removed the switches from the board and put down a layer of nonconducting material over the solder points. I then soldered new leads to the switches and glued them down the board back in their original locations.

But I also decided to get fancy, because well, I could. I wanted to be able to illuminate the top lights on the front fascia when one of the new switches is engaged (like the working switches). So I soldered leads onto the two top row LEDs. The bottom row illuminates the icons of what each button does but since the fascia is blacked out in the two unused switches' locations, that was a no go.
118093


My poor soldering skills aren't going to win any beauty awards but all of this is hidden inside the switch housing, so...

I then drilled a hole in the backplate of the switch housing to let the wires escape out the back. Before buttoning everything up I verified connectivity. This is what it looks like from behind once everything was closed up.
118094


I don't know what I'm going to use the switches for yet. A few ideas are rolling around in my head at the moment. If I go the Arduino route again, I can illuminate the two LEDs when the switches are activated (by the Arduino). If it is something more rudimentary I may not be able to integrate the LEDs but I figured at least give myself the option. We'll see...

If anyone is inspired by any of this and would like to get their hands on the spare switch module, I'm going to post it in the Classified section. After scavenging a few parts, there are still enough "leftovers" to do two more complete switches plus a few other odds and ends if anything else gets damaged during your project. And it definitely helps to see what you're working with before having to take apart your own working set. These switches seem unnecessarily complex to me in the way they operate so I was glad to be able to visualize them first.
 

·
Premium Member
Joined
·
2,281 Posts
@courtier you've been busy! This is awesome. Well done! Can't wait to see what you use them for
 

·
Registered
Joined
·
32 Posts
switches operate through resistance so depending on what you gonna control you could reuse pins on original connector without adding any wires.
 

·
Registered
Joined
·
75 Posts
switches operate through resistance so depending on what you gonna control you could reuse pins on original connector without adding any wires.
@shpuncik I did consider that but my concern was that all of the buttons might share a common return. If that's true and you tap off of it, it could lead to erroneous signals being sent to the car's computer when one of the new switches is activated. I didn't want press a new button and inadvertently turn on the rear defrost for example. So easier (safer?) just to bypass the existing harness.
 
21 - 37 of 37 Posts
Top