300tdi Heater problem

Hi Folks,
Apologies if this has been covered, but whilst I found some similar threads, I didn't find an answer to my problem.
The heater in my '98 300tdi packed in just in time for winter last year. After putting up freezing conditions and ice on the INSIDE of the windows, I decided I need it fixed before this winter sets in.
The switch had been temperamental for a long time, the fan would go off, and playing with the switch always got it back on. So, I'm thinking it's the switch. Problem is I can't get to the switch to check it. I've taken the knobs and the panel off but the housing which contains the switch wont come out the front. I've stripped the centre dash down as far as I can, and there's still something holding it in.
If anyone has any advice, or can point me toward a guide on how to get the switch out, I'd be very grateful.
Thank you.

If you are trying to get the heater matrix out , well it is basically a full dash out job as the thing is huge .

Mine packed in last winter but it was just a blockage which is now fixed . Have you tried to see if there is a fuse for it ??

Hi,
The part I'm trying to get to is the white plastic housing which contains the slider switch, and the three dials that control the heater/aircon.
I have checked all the fuses, one in the cabin and one under the bonnet for the fan/blower..sadly wasn't that simple.
Far as I understand it, it's most likely to be either, the resister pack, the switch or the motor. The fact that it's failed on all four settings makes me think it's not the resisters (as I believe setting four bypasses these), and the fact that the switch was fidgety for a long time, to me, makes it favourite.
Just can't get to the bugger...