2002 Volvo S40 air conditioning acting weird
 

Hey all...so i finally fixed the fuel pressure regulator so my car actually starts properly so now i am onto my next issue!

When i turn the ac on it blows cold...but its like it gets confused if i turn it to auto... it blows at 5 for 2 seconds then stops then starts then stops then starts slowly then high... its like its lost its mind!

If i turn it to level one, two or three... sometimes it works properly and sometimes it hardly blows, but on level 4 or 5 it works fine.

Any idea whats going on?

I got the same issue...

Make sure the control knob is fully left into the Auto position. Put a little extra "umph" when you twist the knob. Don't over do it, just a tiny bit more to seat it fully.

I had mine for several years before I figured this out.

Your fan control transistor may be going bad. I had a similar but not the exact symptoms with mine. This thread may help.
http://s40concepts.net/forum/index.p...fan#msg_116536
Stan

Had that problem too AutoNaut :) That problem manifests as the fan will only work on high. The OP's problem is the fan goes on for a second or two, then off for a couple seconds, then back on, then back off, and on and on. I found it's just the control knob is not 100% all the way in the Auto position. JMHO.