I picked up an EF a couple of weeks ago. Switch to control the air flow through demister, feet, dash was working fine.
Then it started going to windscreen but would go to dash under high vac.
After reading around I suspected a hose had come off or was blocked.
Found the connector in the engine bay and when I grabbed it found out it was either not connected or so loose it came off easy.
Hooked back up but have the same issue but hasn't switched at high vac (yet).

Checked the vac hoses today and on the engine side are clear and connected. Pulled the switch assembly out and all are connected there.

Any ideas? Am lost with this. Hot air vac switch works ok. Not sure about inside/outside switch.

Odd thing (to me) is that the connector has 2 hoses looped back onto each other - the two at the bottom. I thought it might have been to disable a possibly broken flap for in/out.
Still, the vent control was working and then started switching as above.

Thanks!

sounds like insufficient vacuum fault - defaults to screen -

possible hose split/disconnected to vacuum tank or tank itself - which I think was mounted at rear of heater box - try fitting a tank from BA or early commodore to the vacuum hose from engine manifold with a T piece in the hose - may need to block hose feeding to original tank

when you turn car off can you here any vacuum leaking ?

what connector? - may be to block off extra fitting if it was a 3 outlet instead of 2 outlet - is there vacuum coming from fitting or does it need heat up first before you get vacuum