I´ve been trying to find out what is wrong with my ACC unit in my ´86 760 Turbo, It only blows out extra HOT air, no matter what the temp setting is. Tonight I took out the front panel and had a look. I found out that one vacuum hose was blocked behind the radio. I got it loose, checked it and it looked fine. I also checked the temp setting knob with an Ohm meter and it shows variable reading (I think it was from about 30ohm,cold setting, to about 80ohm,hot). I also checked all electrical connections and they looked o.k. I unplugged and plugged them a couple of times. I then checked the sensor in the dashboard with the Ohm meter and it shoved a steady reading with a little dip if I blew on it. Then I put everything together again and took a test drive. But, no change. Still only HOT air. BUT, this time I could hear some soft psssssst sound from where the vacuum hoses go into the control unit behind the glove comp. (I had not yet installed it) I tried to press on it with my finger and the psssst sound stopped. Can this affect my problem or is the temp controlled electronically?

Also, what does the sensor in the dashboard do, does it tell the ACC the correct temp in the cabin or only if it is below or over some temp. What if I connected “over” it (just spliced the wires together) instead of through it? Is there another sensor in the cabin (remember, this is an ´86 model)

Can I somehow check the Freon on the system?

PLS HELP (I´m fried after about 30min drive)