The above examples are of the MK2's COMs units so I decided to show the guts of a Mk1 COMM unit just for comparison.
There are eight (I think) basic pieces to make up to sixteen (theoretical) combinations of COMMs units. There seems to be three circuit card assemblies but only two printed circuit boards. The second circuit card was produced with or without parts for the ESP system (as illustrated below) and the mechanical parts making up the steering angle position sensor for the ESP( I don't have an example with those parts in it).
The theoretical combinations were:-
1) standard config (for manual or auto but no paddle shift)
2) With cruise control (for above)
3) With ESP (for above)
4) cruise control and ESP (for above)
5) with flappy paddles
6) with flappy paddles and ESP
7) with flappy paddles and cruise control
8) with flappy paddles and cruise control and ESP.
Then there were combinations with and without radio controls.
However, I do not know how many of these combinations were actualy used.
Things to note with the Mk1 COMMs.
I do not know if the "standard" PCB configuration supports cruise control (option 2 above). There are extra (unused) pins going to the clock spring and the cruise control is part of the multiplexing going to the BSI, so it's theoretically possible. However car manufacturers don't always produce every possible variant of a model.
All but the "radio controls"(there are other functions they perform) are switched on the main PCB. There are no switches in the stalks (apart from the radio controls). There are drive shafts going down the stalks to the contacts on the main PCB. Complicated but more reliable.
The Mk1 COMMs cruise control switches are mounted in the steering wheel so the multiplexing wires go through the "clock spring" as well as the airbag wires. While I am talking about the cruise control and air bag. This variant seems set up for a two stage airbag system, there are two airbag plugs but one is never used!? The cruise control switches in the steering wheel are unlit (do not light up). However the switches are molded in such a way that they could be back lit. Also the PCBs in the switches have pads for surface mount LEDS and resistors but not enough wires in the clock springs for the separate illumination power!?
The flappy paddles, the ESP and the steering wheel airbag DO NOT go through the COMMs bus. They have their own, separate connectors and are not multiplexed. In fact the airbag wires don't even go through the PCB. The wires go straight from the clock spring to the connector on the side of the COMS unit. This makes the clock spring physically part of the front plate and cannot be removed!
The basic COMS unit housing. Note all the moving contacts that switch tracks on the PCB.
Front plate for the basic unit.
"upmarket" front plate. If the model of car that this went into did not have cruise control
then there was an adapter harness for the horn which plugged into the MPX connector.
For cruise control models the horn connectors were on the end of the cruise control harness in the steering wheel.
PCB for the basic unit.
PCB for the rest. Note the edge connectors on the PCB. While they are not used in the MK1 COMS
I cant see why the MK2 cruise control and radio pods wouldn't work...Hmmm.
Flappy paddle modules. Purely mechanical. They push on switches on the back of the PCB.
Could you convert an AL4 auto to paddle shift...yes but it would take a bit of mucking around.
If you pull your COMS unit apart, it is relatively easy to put back together. However the tube
down the middle is concentric and will fit in either way around but it has two tags that locate in the
back of the steering wheel. One big and one small. This is how they go back in, so you dont need to
look at your steering wheel.
