Strange A/C Problem (98 V70XC)

[bobo2196]

Hey All,

Just wanted to start out by saying that this website has saved me a fortune in teaching me how to fix things on my Volvos on my own. What a great resource!

Anyway, I have a 1998 Volvo V70XC with 159,000 miles on it (roughly)... Done tons of work on it. The latest project is trying to figure out this blasted climate control. It is the automatic unit.

The unit works flawlessly, directs air where it should, at the correct temperature, any time.. Its a dream.

HOWEVER..... If you dont have the temperature knobs in either the totally cold (60 deg) or totally hot (80 deg) positions, the car develops a weird squeaky noise behind the dash. It honestly sounds like a squirrel running around in there. More accurately, it sounds like plastic rubbing up against plastic... Also, there's a soft knocking noise that accompanies the squeaking. But the temperature of the air is correct and it blows from whatever vents I've selected. The noises go away when the unit is switched to either full hot or full cold. Occasionally I get the flashing lights on the ECC but this has not happened in quite some time. The noise persists though. I blew out the temperature sensor with compressed air, still there. I just cant figure it out.

Any ideas?

[jblackburn]

HOWEVER..... If you dont have the temperature knobs in either the totally cold (60 deg) or totally hot (80 deg) positions, the car develops a weird squeaky noise behind the dash. It honestly sounds like a squirrel running around in there. More accurately, it sounds like plastic rubbing up against plastic... Also, there's a soft knocking noise that accompanies the squeaking. But the temperature of the air is correct and it blows from whatever vents I've selected. The noises go away when the unit is switched to either full hot or full cold. Occasionally I get the flashing lights on the ECC but this has not happened in quite some time. The noise persists though. I blew out the temperature sensor with compressed air, still there. I just cant figure it out.

Mine's come back again now that I've started using the AC when raining and not really warm out. *sigh...*

It's the damper motor for the flap between the cool air side and the hot air side between the evaporator and heater core. I think it can be gotten to in a way similar to replacing the heater core, removing the sides from the center console. It's either stuck, or dumb, or both.

http://www.volvospeed.com/vs_forum/inde ... e-install/

I believe the motor is on the passenger side.