Temperature control wacky - no defrosters

beerbelly · Post by **beerbelly** » 31 Aug 2009, 09:44

I am running the temperature controls manually. Whenever I change it, it starts bloweing HOT air, If I set it just 2 clicks above the coldest settings, I get GREAT AC. Also it does not seem like I can switch from dash vents to defroster or floor. The setting for COLD AIR is a little different depending on the output vent. - but it will only come out of the dash vents. Anyone with a hint or a good place to start would be appriciated. What operates the vent selection? Is it motor driven or vacuum, or ????

Post by **billofdurham** » 31 Aug 2009, 12:06

Welcome to Matthew's Volvo Site.

Fault in the ECC system
If there is a fault in the air conditioning unit, all LEDs in the system will flash for 20 seconds. If this fault still exists next time you start the car you should contact your Volvo retailer.

The above is from the owner's manual. Do your lights flash?
Unfortunately, the codes can only be read by a Volvo scan tool.

The vents are controlled by motors.

Bill.

beerbelly · Post by **beerbelly** » 04 Sep 2009, 17:52

No flashing lights. I will try this weekend to see if I have any codes.

beerbelly · Post by **beerbelly** » 06 Sep 2009, 07:30

No Error codes thrown.
When I move the temperature setting, the damper motor goes all the way down and stays. If I put it 2 marks above the coldest setting, it opens and lets in ice cold are, untill I touch the controls again. ps fan works on all speeds.

beerbelly · Post by **beerbelly** » 07 Sep 2009, 13:42

OK I am half way there. I touched up a couple of the pots that didn't had solder on the top of the board through hole, and then cleaned as much of the old FLUX off the board with alcohol. I also verified the pollen filter was ok. It seems that I can now get air out of all the positions, including defrosters. I still have a problem with the temperature of the air going from very cold to very hot with just a little turn of the knob. I was wondering if it is possible that the board had been removed before, and when they put it back together, the knob got moved, and now the pot is not in the correct position. Is this possible? Any idea on how to verify that the pot is set correctly? What resitance for the coldest and warmest settings?