I am having mysterious problems with my ACC. I have a 96' 850 gle with individual controls for each side (not sure if that is special for my year/model?).

It blinks 18 times (timed evenly) when I start the car. It does not always do this. I also have some strange behavior such as cold air out of the middle vents with hot air out of the side vents on auto, when I switch to another mode the air warms up in the center vents. The AC has quit at strange times. It will kick back in when and if it wants too.

I have found no ODBII codes but I am not sure if I am reading the ACC ones. Do I need to do anything special to access these codes? I have replacement sensors that I got from my local boneyard but I cannot be sure what to replace. I do not want to try shotguning. It may also be bad solder joints. I can reflow them but once again I want to be sure that this the problem.

Anyone's experience and/or insight would be greatly appreciated.

Per my 96 owner manual;

"The REC and ACC OFF lights will flash for approximately 20 seconds if a fault is detected in the Electronic Climate Control (ECC) system. If this flashing recurs the next time the system is switched on, the climate control unit should be checked by an authorized Volvo dealer."

Last time the lights flshed in my car, the temp sensors located above the "Oh Sh*t" handles in the drivers and passenger comparment had filled with dust. The dealer used a can of compressed air - like the kind used for computer keyboards - to blow the sensors out.

Good luck.

Oliver

Over a million Volvo miles and still smiling....

Spot on! The 18 blinks do last exactly 20 seconds. I have read before about vacuuming the sensors but that did not make much sense to me since being in the electronics business I could see that vacuuming would not get to the dust. I am baseing this on the dust buildup observed in the sensors I got from the junkyard.

Anyway, removing the covers and giving each sensor a quick shot from my CO2 blaster solved the problem. No more blinky!

I will see if this solves the behavior problems, at least I am on the way to figuring what is going on. Thanks.

I had something similar on my 760 and it was because the vacuum lines were leaking .
my 97 850 will blink now every once in a while , then goes away.