Another A/C Problem

[ces63ss]

sorry I tried to search for the answer but could not find it. I have a 04 sss and recently it stopped blowing cold air if the truck is not moving and I can hear i wird sound coming from under the dash. Sounds like the actuator trying to move to the fully open position when I select full vents. If I select just off the vents and partially vents and foot vents it stops making the noice. I think the a/c freon might be part of the problem but how do I check the resistor on the flapper door? Is there a How-To?

 

thanks, Ces

[blackbeast ss]

if the blower is blowing then your resister is fine,do you have access to refrigerant gages?? that wirl sound is the refrigerant flashing in the metering device (normal)

[wody]

first things first...does the compressor engage with the a/c on? if it does, simply feel the low pressure hose (the larger of the two sizes). its should feel a little warmer than ice. if it feels warm you may have a low charge or worst case scenario a restricted orifice screen (failed compressor). if the line is warm, get your pressures checked to determine if it's a low charge or obstruction. obviously the pressures will be low with a low charge, but and obstruction will damn near pull the low side into a vacuum.

 

after reading your post again, it sounds like it's a low charge or your fan clutch is worn. while driving there will be more air flow over the condenser than there is when standing still. however, im leaning more towards a low charge.

Edited September 28, 2010 by WODY™ (see edit history)