Where and what does one read climate control fault codes from? I was told that the blinking lights on the recirc and the other button can actually be counted to tell you what the error is? Is that true? I do not beleive that the codes are stored in the main computer, as I have the blinking lights and nothing showing on my ODBII reader, but of course a Volvo scanner might be able to read them from the main computer? Even though we are slated to get 15" of snow over the next 24 hours here in upstate NY, I would like to address the a/c issue before the summer heat arrives. I believe the evaporator has been done on this car.

The blinking lights mean the ECC is no longer in the "auto" mode. Everything else will work manually: fan, vent control, AC, heat.

Mine, until a few days ago, would blink on intital start up. After the car warmed up, a restart would give me green lights. Diagnosis, dirty cabin temp sensor.

To get to the sensor, the radio needs to be pulled out. I balanced it in the shift knob. Then the ECC unit gets pulled out, but it is pressure fitted and initially does not want to budge. When the ECC unit gets loose it wants to fly into the rear seat!!

Then, put the radio back in and unplug the ECC. Reach around through the ECC hole to the sensor behind the little grill in the right most switch plate. There are 2 plastic tabs about half way down the plastic barrel. Push the tabs into the barrel and remove the sensor. Note the position of the plug before you pull it out, the plug must be in the same position when you put it back in and let it snap into place. Do not unplug the sensor until it is out of the dash, you don't want it to fall on to the driver's side knee bolster.

Clean the sensor with a pipe cleaner, be very careful with the copper tubing it is quite fragile and cannot be bent!. Blowing on the fan portion helps get some of the residual dust out after pipe cleaning it.

Reinstall.

Klaus
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Always willing to listen, just not able to take direction.

You can try this (I believe it works for MCC, not ECC, so if it doesn't work its dealer only, sorry):

Also your volvo should be able to diagnose several problems on its own. To check if it has a code start with your car off (key in position 0) Then move forward to either I or II and look at the REC button on the climate control, it will flash one time if there's a code. If it flashes push the REC button twice, and only twice, when the light flashes and within 2.5 seconds of turning the key. The REC light will flash corresponding to whatever code it has. The code is three digit and the car will tell you one digit at a time. It is on for one second and then off for .5 if its counting up (so if the first number is 2 you'll have one second on .5 second off one second on) Then when it pauses for 2 seconds its switching numbers. After it finishes the first code (remember 3 numbers to a code) it will be 5 second delay between codes, if there's more than one. Therefore if you get the code 2-3-1 and 1-1-1 you'd have this sequence : 1s on, .5s off, 1s on, 2soff, 1s on, .5s off, 1s on, .5s off, 1s on, 2s off, 1s on, 5s off, 1s on, 2s off, 1s on, 2s off, 1s on ...
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If you're not driving it "like its stolen," are you really driving?

That procedure doesn't work on my 1998.

I assumed, correctly, that it was just a dirty cabin temp sensor.

Klaus
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Always willing to listen, just not able to take direction.