Tools required:
T25 Torx
Phillip's screwdriver
10mm & 13mm for engine battery ( on mine it was)
Long nose pliers
Terminal removal tool
Soldering iron, heatshrink, connectors
Alfa Romeo 147 cruise control stalk p/n 735365520
4 pin brake switch
Obd cable & multiscan ecu (free version should be ok I believe, i had the paid version)
This is based on my experience on a 2004 Fiat ducato chassis- lhd
My vehicle was already wired meaning that the cable connections from the ECU to the brake switch, black connector, dash light were already there.
As always, this is entirely at your own risk. I would urge to double and triple check wiring diagrams before embarking on this.
Cost... a couple of hours of your time, and maybe less than £30 depending on the cost of the stalk.
1. Disconnect battery
2. Remove cowling under steering wheel
3. Remove cover for fuse box on driver side
4. Find black connector near fuse box. One side of it is already terminated with pink, red, yellow/black, white/purple, thick red & black/blue cables . These come from the ECU
5. On the alfa cruise control stalk, use terminal removal tool and extract the cables and pins.
6. Cut stalk cables, ensure to leave enough to allow you to extend the cables to the fuse box area
7. Using the wiring diagram, connect 4 if the extended stalk cables to the black connector found at the fuse box. This can be tricky due to space. I used the long nose pliers to pull the terminal through.
8. Remove existing 2 pin brake switch and use 4 pin brake switch
9. Link yellow alfa stalk cable with terminal 3 & 4 at brake switch. Alternatively, there is a connector at the passenger side. Remove the section above the glove box. Yellow cable can be connected here and also link 2 pins though cant remember pin numbers for this. The Italian link will tell you.
10. All connections made? Double check and reconnect battery.
11. Looking at where the indicator is mounted, there is a part that the alfa stalk can screw into. You will need to cut a recess in the lower cowling in order to refit it.
12. You may or may not need to do this part. I had the equipment hence doing it: Connect obd cable and start multi scan ECU. Select vehicle and connect. Once connected, select "parameters"
I used this programme to check brake switch and cruise control buttons worked correctly.
13. If all was ok, road test the vehicle.
On the Italian forum, some members said it took a few key turns before the cruise dash light came on
I think others did not need to use an obd cable to activate it.
If the vehicle is not pre-wired, it is still possible to do the retrofit. Connection needs to be made from the ECU.
References:
Where I read about it:
https://forum.camperonline.it/tecnica/meccanica/cruise-control-alfa-147-su-ducato-244-aiuto/222555
Ducato cruise wiring diagram
http://4cardata.info/elearn/244/2/244000001/244000003/244000005/244001961