Below is a condensation of the text of the thread on that other forum, with thanks to Joe. I haven't included the photos, but I'm sure Cha can point anyone who wants them in the right direction.
"Many of us, and many more who'd like not to have been there have suffered this dreaded failure with their exxy's. Speedo cable breakage!
I've spoken to people asking for easier ways of replacing said speedo cables, much has been written about the merits of leaving the inner cable dry, lubing it, pressure lubing and correct alignment at the join between long and short cables in the case of the 1500 models.
I few years ago I even had a phone call from someone asking whether the quote from her local garage to fix the speedo cable was reasonable. Needless to say I suggested that over £300 quoted might indicate the garage she'd been to didn't really want to do this awkward job for her! I suggested she try another garage, since I didn't really fancy doing the job for her either..... I wasn't being not unreasonable, I quite like to help someone in need, and will happily pass on any tips or experiences I've had (suffered)...... but I'm not a registered charity!
Rather than replacing that broken cable for new, only for it to break (or maybe not if you're lucky), I was sure they'd be a better alternative. As usual I looked to more modern FIATs for a solution.
Most more modern and current FIATs use electronic speedos. Sounds fancy, but the basic technology already exists within the X1-9 rev counter mechanism. In layman's terms an electromagnetic assembly affair within the console awaits a signal (electrical pulse) from your ignition coil to discover how fast your engine is rotating. This is the basic principle behind many more modern speedo assembly setups...so back to the local breakers yards to clamber over some crashed and rusting FIATs...BINGO!
1. Your X1-9 speedo cable starts its long journey to your speedo dial at the gearbox. Look at the gearbox of your chosen more modern FIAT.... Perhaps where a speedo cable end once lived in the past, you'll find a funny little black plastic thing with three wires coming out of it.... This will unscrew in the same way as the X1-9 speedo cable outer will...only it should be easier to undo!
The black plastic thing is actually a sender unit for an electronic speedo. Three wires coming from it include black, which you should wire to a suitable earth within the engine bay.
The red, or blue and red striped wire, which needs a switchable 12v positive (you don't want it on all the time).... As it happens the later SE and Gran Finale models have non working thermoswitches on the thermostat housings to aid autochoke operation....select the positive wire from this circuit will do nicely, or tap into another switchable positive within the engine bay of your choice.
The blue wire is the pulse/trigger wire, which needs to be routed back to your speedo dial/ console assembly. A handy route has already been made for you if you simply remove the inner broken cable from your original cable outer sheath (thank you Frosty).....Feed your blue pulse/trigger wire back down towards the console end.
2. Screw your sender unit onto your gearbox. Note that the thread is the same type as your exxy gearbox. However, some units have a deeper recess before the start of the thread....... I believe some Puntos and Tipos have this design. Worth checking when you grab a handful from your local breakers yard..... The units also have a reputation for unreliability, all the more reason to grab a few....... Although I've not had a problem myself.
3. Next comes the tricky bit! Examine the electronic speedo unit in your chosen more modern FIAT. Note the dial increments..... There aren't many that have, for example 60mph where 60mph appears on your X1-9 dial!.... See the photo of the Punto dial on the left and Tempra dial on the right...both are different to each other...and to the X1-9. Ideally you want to find an assembly that has the same increments as your exxy. To my knowledge late model Stradas and Regatas are the only FIATs with the same increments with the electronic option. If you can't find a Strada or Regata with electronic speedo assemblies, either forget the idea...or if you have some electronics experience, modify the PCB, which you will also be getting from the donor car. I'm not going to go into what circuit modification was needed here. It was a bugger to do, with many failures and near misses.
I never said this modification was easy!
4. Now you have your sender unit attached, pulse/trigger wire and , hopefully, the speedo assembly ripped from the console of a donor FIAT (together with the PCB)
Remove the console from your X1-9....Or, preferably (read; highly recommended!) get out your spare X1-9 console, and mark up how you would like the new electronic assembly to fit into the X1-9 console.
The electronic unit is larger than the cable driven exxy unit, so be prepared to use a Dremel / mini drill to remove excess plastic in the console housing
5. Mount the electronic unit in the exxy console housing. With careful housing modification, this should JUST fit into the unit, and hold itself secure. The use of a hotmelt gluegun at this stage is up to you....But you're on your own if you need to remove the unit at a later stage!
Reassembly the console and secure the PCB externally. Alternatively if your name is Harry Houdini you may be able to fit the PCB within the console assembly...but I doubt it!
In my case, the speedo assembly was taken from a Punto, with a modified PCB, and some cursing it works just fine..... as may be noticed on the photo, the pulse/trigger wire for these cars WITHIN the console area is yellow...then changes back to blue to connect up to the end of wire fed through the speedo outer sheath (ignore the black box inverter and red/black wire around the rev counter area... this is related to modified console illumination)....which has been in previous mag articles.
The odometer reading is a real pain to sort out..... still not perfect but readable. I can't be accused of 'clocking' my car, surely.... after all who'd want an X1-9 that had done a genuine near quarter of a million miles!"
