Fiesta Stereo Buttons Stopped Working - Fix!

[the_scotsman]

I have a 2010 Fiesta Zetec as a second runaround car. Recently, all the stereo buttons stopped working. When I turned on the ignition, the stereo buttons worked for about a second, then stopped responding.

Googling shows this is a fairly common issue on the Fiesta. The only other fix people suggested was a new button unit. They sell for well over $100, so I wasn't even contemplating that. (hey, I'm a Scotsman!)

I pulled it apart, did some troubleshooting. I checked for shorts, measured the resistors and caps, the usual things to look for, but found nothing. I removed the circuit board from the housing and connected it back up to the car, feeling for any hot spots on the board. Nothing got hot, but one chip got warm, after only just a few second.

There are only 2 chips on the board, one to communicate on the bus (transceiver), an another that, from memory, does the processing. The transceiver chip was the one getting warm, and it makes sense that if that one was faulty, buttons would work for a brief period, then stop.

So I bought a replacement chip online (mc33911bac), which is readily available, and only cost $10.

I swapped the chip out with the new one. It's easy if you're decent with a soldering iron. Just need to be careful as the pads are very delicate and easily damaged with too much heat/pressure. (I found it easier/safer to remove the chip with a heat gun instead of the soldering iron). I then connected the board back to the car, tested the buttons, and success!

Such a rewarding fix! Especially when the alternative is over $100.

The images are zoomed in, the chip only measures 7x7mm.

Hopefully this post might help someone else in the future, as it does seem to be a fairly common issue when searching Google.

Circuit board before I did the chip swap


Chip removed and board cleaned


New chip in!