Supercharger not quite operating correctly,?

[A1EK]

Hi Guys
I have a W208 CLK 230 Kompressor. 2 days ago I floored it through a tunnel (as you do!) and the car accelerated lovely as normal, however when I slowed down the car was lumpy and missfiring. I managed to source the problem and found one of my igniation coils had gone, so I replaced and eveything was fine once more, although I thought?
My supercharger seems to be on constantly, I have disconnected it to test if its on and there is a noticable loss of power so it is partially working but its not building the pressure as before.? In park I used to be able to rev the engine to about 2300 revs and there was a noticeable note change , you would hear the by pass valve opening near the airbox and hear the whine. IF I disconnect the supercharger at the plug I see the clutch wheel engage and disengage so I think mechanically the unit is ok and its too much of a coincidence that I have this fault at the exact same time my ignition coil went. I think perhaps a voltage spike has caused an electrical issue?
Something is telling the supercharger to be on all the time so I suspecting its a control issue? Can anyone give advise on where to check?

 

[Dieselman]

It is likely to be the recirculating air flap that is causing it. The motors have a habit of shorting out and taking the ECU drivers out, so don't delay.

 

[A1EK]

It is likely to be the recirculating air flap that is causing it. The motors have a habit of shorting out and taking the ECU drivers out, so don't delay.

Do you know if there is a way of testing the motor is okay?
I removed the rubbe pipe so I could see the flap and turned the key just before you crank, the flap moves slightly but stays open. When I start the car it remains open when reving.

 

[Dieselman]

Sounds like it's faulty, but you could try shorting the -Ve lead to Gnd and see if it pulls shut.