Boxster 986 frost issues

[DaveBBOXSTER]

Thanks for the last two replies - much appreciated. I did look up on here about the ignition switch and seems a good fix to try first as it is cheaper...
Will heed your advice and try that and report back.

[DaveBBOXSTER]

UPDATE - Took off ignition switch yesterday...Spent over an hour attempting to get at the two grub screws from under the dash with no success. It turns out the UK spec Boxster, being RH drive, has the screws in a position that they cannot be seen or felt from under the dash. Eventually took off the RH side vent cover (with the light switch below) and could at least see the grub screws from above, BUT they were coated in a red blob of something (Loctite or sealer) and the slots were hidden too...after gently scrapping it off I released them just enough to get switch out NEVER EVER TAKE THESE OUT FULLY NO NEED - Even working from above with one hand in vent hole of dash it took 15 minutes, as access is really tight!
Managed to break the plastic side air vent catch getting the vent cover out it caught or I was too careless. Did a bodge repair by drilling the flap where the little plastic ball should be and inserted a small screw plus spacer nut so it opens and shuts until I can get a new cover. I may leave it until it fails, as it's not visible.
Fitted new switch today (£15) and the wipers now work via the stick and the radio stays on BUT the heated mirrors stay on and cannot stop them via their switch or by taking the 5Amp fuse out! HOW CAN THEY CONTINUE TO WORKWITH NO FUSE IN?

This shows switch


Bodge fix repair to vent flap
View through vent flap on RH Drive UK car

[DaveBBOXSTER]

Hi Mike F,
Yes I do have a cover that just goes over the roof section and did use it one winter and it was great (as the roof screen leaked as it was split at that time) BUT the wind blows and the cover plus ropes scratches the bodywork so it put me off ...I may do a cover with a duvet under to keep it warm! It is the cold air freezing inside that is the problem as it causes frost on the screen inside...

[DaveBBOXSTER]

Taken car out and the only thing now wrong is that the heated mirrors stay on and when driving the switch light is bright and it won't turn off at the switch...When stopped with ignition off and key out the switch light goes dim and the heating of mirrors stops. Am now thinking it could be the switch itself that is faulty? Looked behind cover but couldn't get switch out...will need to look that up.

STILL I CANNOT ACCEPT THAT the heated mirrors can still work with the fuse removed this makes no logical sense and is there a separate module or unit that controls the heated mirrors? mine is shown as 5Amp fuse \ Row C position 7 (from left?) referred to as "Terminal X" Why is it called terminal X? Seems strange that it just has a 5Amp?

Surely, if I take the heated mirror switch out or off it must stop working...If so it must be a broken switch!?!

[DaveBBOXSTER]

Removed heated screen switch but the glass stays hot. It did go off at one point during a 12 mile drive but came on again when switch was put back.
Checked CLU under seat and it seems 100% dry, clean and in good condition - picture attached.

All other bad symptoms gone except this heated mirror issue

[DaveBBOXSTER]

THANKS Mike and Particlewave,
Just went out and checked D2 30 Amp fuse it was OK and even without it in the switch was lit.

[DaveBBOXSTER]

Particlewave, just pulled the #4 block defrost relay out and NOW the switch light has finally gone out...THANKS
Does that suggest or mean it is causing the issue and is faulty and needs replacing?

If I can get a new one maybe worth trying