I found a design fault in the stalk assembly of my 156 that prevented indicators cancelling when turning right (cancelled OK when turning left). The stalk assembly is Made in Australia (a bit of a red rag to a bull for a Kiwi to see that
There are two 'sharks tooth'-shaped fingers touched by two nubs on a rotating white sleeve. At least on the 2003 model, the sleeve is nothing to do with the clockspring - it is part of the stalk assembly. Taking apart the stalk assembly is one of those prying moments when springs and bits fall out, and the next day you realise that the headlights are now always on...
So test thoroughly after reassembly...
The nub just slides under the turning-right finger by a hair's breadth (there is ample contact to the turning-left finger, but there is an alignment problem that leaves most of the nub doing nothing at all. The fingers need to be repositioned, either by placing a washer underneath them (which might jam the fingers), or by melting/extending the plastic on the turning-right finger. That is what I did - I heated and reshaped it, and just to be on the safe side, I built it up with a special powder-and-super-glue material that sets very hard, very fast.
The main problem for me was not the fixing of the indicators, but instead the refitting of the steering angle sensor - which is attached to the stalk assembly - it is imperative that the rotating black sleeve goes back in the same position. Mine didn't, and I spent hours trying every possible position. The sensor has no end-stops (it rotates infinitely) and taking the sensor apart reveals nothing except a fascinating construction (two different-sized gears with magnetic sensors, moving over ICs on a circuit board).
The only solution, once you have lost the angle sensor position, is a trip to the dealer or specialist to connect diagnostic equipment and reset the angle sensor position. My Alfadiag cannot connect to my ABS ECU, but the specialist's 'SuperScan' software connected and performed the reset straightaway. Mine was out by 556 degrees, by the way!
I've attached a few pictures that might show what I'm talking about. The first photo shows how the turning-right finger misses the rotating sleeve nub. I don't understand how this would have ever worked properly and I seem to remember a recall to replace these stalk switches when the cars were new.
The second picture shows a possible solution - a copper washer to raise the fingers - which unfortunately interferes with the delicate spring-loading of the fingers and causes a possibility of jamming when the indicator lever is operated JUST as the nub touches the fingers (this happens on roundabouts when you indicate in the opposite direction to where you're turning and get that unmistakeable snapping sound).
Another possible solution would be to extend the two nubs on the rotating sleeve - but I expected that any such extension would probably break off. For some reason, I had a better feeling about modifying the turning-right finger instead.
The third picture shows the finger re-shaped (i.e. melted) and built-up with the glue and grey-coloured powder. (Pity about the camera shake - can't use a flash up-close as it washes out...) In the background you can see the various switch contacts and sliding plates that require great care on reassembly to get them engaged with the various parts of the stalks. The fourth picture shows how the nub now contacts the finger. Ugly but much more effective.
There was no evidence of wear preventing the contact before - it was just a design mistake. I think these parts are far too small anyway - I reckon they should be large plastic toggles and roller-levers, as in a 1980's FIAT Uno or 1970's FIAT 128. I'm always amazed by how designers of these parts manage to ignore the perfectly-functioning designs that have gone before and instead come up with something new and problematic. And then we wonder why the 'click' of the stalks isn't as solid-feeling...
My indicators have worked perfectly for several weeks now - a pleasing result.