The WD40 didn't work.
I confirmed the MB part number in the MB parts catalogue and then I ordered one from Global Parts.
There appear to be variants, so I ordered one with the guide that appeared the same as in the opening next to the fuel cap.
It came yesterday - So I gave it a try this morning.
The new item is as in the photos attached.
The end of the guide can be removed by twisting and pulling the end, which looks the same as on my car.
By opening the small hatch in the right-hand boot side-wall, I could put my hand in and feel the item.
The steel operating rod does not appear to be enclosed in the black plastic guide tube.
I was rather hoping to remove the guide tube end and then remove the mechanism towards the rear of the car.
The problem is I can feel it and I can feel where the electrical connector connects into the plug on the body, but there is very little space.
There is no space to remove the electrical connector.
It is not clear how the mechanism is removed from the car.
The power lead is a two wire lead to the two-pin plug.
I tried the unit that I had bought, and found that the unit works (lock and unlock) by reversing the polarity of the 12 volt supply on the two wires.
There is no earth return to the circuit.
There must be a small dc motor in the actuator which works in one or other rotions..
By feeling round the unit in the car, I found a little manual rotator.
When I rotated it, the operating rod wound out to lock the flap.
When I pressed the key button to open the car, the rod retracted sharply to its unlock position.
Pressing the lock-button on the key had no effect.
Several times, I locked the car by winding the little rotator, and then retracted the rod using the unlock-button.
So - This says to me that the polarity in the two wires is not reversing and this is what is stopping me from locking the flap.
However - The wires are not broken and are both attached.
Otherwise there would not be a complete circuit.
My next move will be to break into the control wires and put a meter on them to check whether there is a reversing 12 volt supply.
I need advice:
1. How do I remove the actuator ?
I was reluctant to remove the boot liner without seeking advice.
It looks a lot of work and it may take me no further forward.
The actuator may be ok.
When I break into the wiring, I can apply a 12 volt supply in both polarities.
That will confirm whether the actuator is kaput or not.
2. Is there a module to supply this actuator ?
It must be separate from the door and boot locks, as they all work on both the lock and the unlock command.
I would be grateful for any experience and advice.
Thanks.
J.
