Saabscene Saab Forum - Saab Technical Information Resource banner
1 - 10 of 10 Posts

·
Registered
Joined
·
444 Posts
Discussion Starter · #1 ·
I recently got fed up of my acc not working properly, blowing cold unless turned to HI setting. I'd previously had the fromt off the cabin temp sensor and cleared the fluff out to no avail. This time I removed the unit from the car and found loads of gunge around the fan unit. This is pretty small and can be stopped from running by a bit of muck inside. I cleaned it fully with tweezers and contact cleaner and hey presto, the ACC now runs exactly as Saab intended. Well worth the 20 minutes it took.
Hope this helps any fellow winter shiverers

Anthony
 

·
Registered
Joined
·
444 Posts
Discussion Starter · #5 ·
Yes Trejon, hope I can help.

The ACC was blowing cold almost all the time unless HI was selected and then it would just blow max hot all the time. The cabin temp sensor is behind the circular hole vent thing, just below the heated seat switches on mine. If you pull the front off you'll see the thermistor that senses the temp and generates a resistance sensed by the acc unit. Behind this is a small fan (can't really see it until you remove the unit. I assume this fan is to prevent general localised heat soak and to keep air moving over the thermistor to give a representative cabin temp. Mine had all sorts of fluff around it so the fan wasn't spinning (mine made a sort of mini clattering noise trying to turn). I assumed that as there was no air flow, heat localisation from the stereo and other electrics nearby was 'fooling' the sensor into thinking the cabin was hot all the time and therefore not needing any more hot air to reach, say, 26 degrees c. Therefore it blew cold to try and bring things back to 26 degrees. Got rid of the fluff and cleared it with contact cleaner until the fan span freely, and now it works fine and has done for a while now. If you select a temp the acc unit basically sees if it needs to blow hot or cold to reach that temp and adjusts accordingly. Any spurious readings from the sensors will mislead it into trying to obtain that temperature. If I remember, yours is blowing hot all the time?
Different to mine but it's worth trying. Sadly, I don't know the thermistor resistance for a given temp right now. I'll take some readings and post hat they are. HTH
Anthony
 

·
Registered
Joined
·
75 Posts
Anthony.

Thanks very much for that, I will certainly check it out. Mine isn't blowing hot, it just won't get cold enough. Having said that, I went out yesterday to visit friends, (John and Cathy Curlie)late of Saab Owners Club of GB, who live about 45mins drive from me and low and behold the air con seemed to cope OK and this was on a 35 degrees day!! I really can't figure it out!! I just hope it is not short lived. The forecast is for 37 Degrees xmas day. Guess we won't be having Turkey and trimmings after all!!
 

·
Registered
Joined
·
776 Posts
Called up an old thread, saves starting a new one.

An old chestnut though....

ACC unit blows full-power hot on the LO setting, I recalibrate by pushing top-left and bottom-right buttons, and it goes thru faults: o, 1, 2 etc..

If it shows 1 or 2 faults, it goes thru the motions, and still blows hot after it settles down to LO display..

If I take the offending glove-box fuse out for 10 seconds or so, then recalibrate the Unit, it works ( sometime the 2nd time, not fist go). Have to do this palaver most days !!

Its driving me nuts,and thats not the steering wheel down my trousers (sorry, can't remember where I read that one)!!

any ideas over the Aircon problem.

Cheers,
Andy
1994 9000 FPT
 

·
Registered
Joined
·
776 Posts
Sorry, will explain better.

When ACC on "LO" setting, it quite often blows hot air (like.. full-on fast and hot !).
If I reset with the 2 buttons, it shows maybe 1 (one) or 2 as number of faults in the display. It then goes thru motions, sets back to "LO", then starts to blow hot air again. If I repeat, usually I will get the same result....

If however I take the fuse out for 10 seconds or so, then replace fuse again, and THEN re-set ACC, it MAY give "1 0r 2" faults as before, and still blow hot, but after a second "re-set", it will almost invariably show "NO FAULTS" (ZERO - 0 ), and after going through the motions, will re-set on "LO", and blow nice cool air afterwards as it should.

I dont want to bother anyone too much on this, it is just annoying at time.

Cheers,
Andy
 
1 - 10 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top