It's been ages since I could contribute to the forum. Been busy all these days travelling and spent only 60 days in India over the last 18 months. My Punto Emotion 1.3 MJD was lying idle for a long time. I was never happy with the factory fitted OEM stereo. I had succesfully amplified it using a Blaupunkt THA 555 PnP and replaced the factory speakers with Polk db6501 components in the front, Polk DB651 coaxials at the rear and a JBL 10 inch Sub. All thanks to the 5 channel Blaupunkt amp. Everything was good, till I started lacking USB and Bluetooth on the head unit. To blame, of course, the rental cars I have been driving in the US and Sweden over the past few months.
Fiat being not so popular in the states, I couldn't get hold of any accessories. However, this time around, being in the EU it was heaven for Fiat accessories (aftermarket). I was actively looking to replace the factory Head Unit in my Punto. Fiat's electronics are a little too complex for our ICE installers to comprehend. The whole CANBUS neural network with each end point being a node and everything controlled by the body computer (ECU) is wonderful technology. Unfortunately it doesn't allow much customization. Solution is available though, will get to it in a bit!
When I had pulled out my head unit to install the PnP amplifier myself, I had taken a few pictures of the pin out diagrams on the head unit. No surprises to notice no ACC/Ignition wire/lead available for an after-market stereo. I have seen a few posts where this wire was pulled out from the 12V accessory socket. I never wanted to splice any wires or add any additional load to the factory fitted nodes (CANBUS terminology). The CAN A and CAN B are essentially the two wires which send out software commands to literally everything related to the head unit, these include Ignition, Speed Pulse, Data to the MID, Illumination et al.
The image on the factory fitted Blaupunkt Stereo
The Solution:
I tried to look for Plug and Play adapters which could help decode these software commands from the ECU and give me a plain analog input which I can use for an aftermarket stereo. A 2 week long research, phone calls and emails finally gave me the proper solution - a CANBUS adapter. The logic is pretty simple - Plug one end to the factory ISO adapter, and you get the other end (ISO Standard) to plug it to any aftermarket stereo. You get the Ignition, illumination and Speed Pulse wires too! What I purchased is below. I just love the plug and play harnesses. An additional advantage is you can still preserve the Steering wheel control interfaces by purchasing an additional stalk adapter specific to the after-market head unit. I do not have steering wheel controls, so was not interested to buy one.
The green and white CAN A and CAN B wires from the new harness. These go to the mastermind
The mastermind which translates commands from ECU to analog signals.
The Whole unit:
The plug and play connector which goes to the car:
The standard ISO connector for after-market stereos:
The ignition wire is now a part of the standard ISO connector
The steering wheel stalk adapter (Got this free as I ordered a JVC one, changed mind to Alpine later, but since I do not have any steering wheel controls, wouldn't need this)
This CANBUS adapter works with over 180 cars and is self programming. One less thing to worry about. This gives me a flexibility to use it later in case I wish to part with my Punto (highly unlikely).
More documentation:
![DIY Solution: Fiat Punto after-market Stereo + steering mounted controls-whatyouget.jpg](https://www.team-bhp.com/forum/attachments/car-entertainment/1082357d1691543987t-diy-solution-fiat-punto-after-market-stereo-steering-mounted-controls-whatyouget.jpg)
Now that I have this adapter, I was looking out for headunits. I decided on the Alpine CDA-137BTi. Has literally everything I can ask for. Once I plug it in, I would let my ears decide if I need to upgrade the 5 channel amplifier to a 4 channel + a monoblock. I might still need a month to try that out as I am stuck in Sweden till end of May.
Any question regarding this solution are welcome!