Explain how to do it:

Look at the fuse box near the battery under there is 4 wiring plug. If your don't have then you need to wiring up from ECU pin number 41, 58, 8 and 9 (SEE WIRING DIAGRAM)

1) Check the fuse number F1 70amps is insert and go interior look at the fuse number F37 10amps, F42 7.5amps, F49 7.5amps and F53 10 amps if your is not there insert it. The clutch switch check if your still have them if not you can buy them from EBay £6

2) My Alfa 147 cruise control stalk from scrapyard £14.99 with 5 pins (5 wiring) remove undercover from steering wheel, the cruise stalk arm holder remove the second hole (see picture) with file till the hole disappear otherwise it won't fit, tight up with one screw.

3) Drill a 7mm hole under near the heated fan motor on the passenger side, buy 4 of 5amps 3 meters wiring and put it through the hole from inside it will be more easy.

4) Cut the plug off from fuse box in the engine and tight it up 4 wires with pearl terminal blocks, and connect it to your own 5amps wiring from the interior (to make sure to put up label and write the colour name at end of wire at interior)

5) Cut off the cruise stalk plug and fit same 5 pearl terminal blocks

the colour wiring match is:

Switch on/off: yellow to the ignition wire with 7.5amps fuse

Resume button: green with green/yellow

info send to ECU: orange with light blue

- decrease speed: dark green (some have black or navy) with red/grey

+increase speed: red with red/yellow

6) On HGT and Eleganza already have setting from ECU which is not required to relearn, you can see cruise light icon on speedometer when you switch it on.
(But I am not sure about the Sporting, Dynamic and the Active mind need to use Multiecuscan and relearn it)

Test drive to make sure the cruise go off when touch the brake, clutch some other Fiat it will go off when apply the handbrake and pull out of gear.
Try to use the increase and decrease speed knob and the resume button,

if everything is works fine then tape up all the connect to protection from damp/wet and short circuit then refit the undercover.

Good luck!