Latest on the 560SEL:
I took the seat out again and had a look at the adjuster.
Using a power probe, there was constant 12v to one of the pins of the motor, and nothing at the other. When the switch is pressed, the voltage goes away.
This doesn't seem right. The motor works by sending current in different directions depending on the way you want the switch to go.
However, If i used my power probe and apply 12v + ground to the plugs, the mechanism will move in whatever direction I want.
I assume therefore I have a ground or switch problem. I needed to fit a child seat, so I have put the seat back into the non-recline position for the seat.
More here:
https://www.classicjalopy.com/2020/06/w126-reclining-rear-seat/
Looking at the EPC, it looks like there are a few different part numbers for the switches. Normally it tells you what has been superseded by another one.
The first two part numbers are NLA, but the second two are not. Since W126 parts are going NLA so rapidly, I may pick up a couple of these switches so I have them on hand if needed.
Next week the W126 goes in to have the guides and sprockets done (chain and tensioner was done without this for some odd reason), motor mounts and a few other misc things.
I plan to have the car ready for the joint Mercedes / RR club drive in two weeks.