1.. You are likely low on refrigerant. Cylcing of the compressor is expected once the temperature at the evaporator is satisfied. Of course, this could also be an electrical issue but rarely. Be careful, you can also be overcharged. Over/under charging is easy with R134a refrigerant, it is not like our old R12 which was not fussy. The best step might be to take it to a shop, have the system evacuated and vacuum pulled, and them "properly charged".
You might be using compressor life wastefully now.

2.. Vents are ususally controlled by vacuum. Hoses run from engine vacuum to the dash inside to control the vents flaps. Check in the engine compartment, not sure if both sides are routed independantly or if the vacuum loss could be under the dash area.

3.. Try disconnecting the battery. Good idea to keep radio off when doing so, some units were fragile to microprocessor burnouts. The codes might clear. Leave it off for a few minutes. Otherwise take it to the shop, I don't think the codes are self served on a 96.

These are only suggestions. I don't own an 850. RWD enthusiast...

Good luck.

Greg Mustang
Montreal - Ottawa
Canada