A/C turns on when Fan Control switched to manual? 1998 S70

LowEnergyParticle · Post by **LowEnergyParticle** » 20 Aug 2007, 11:32

Hello everyone,

I've got a 1998 Volvo S70 non-turbo built for the US market with 110K miles, purchased and run in southeast Texas. Until a month ago, the AC has always run fine.

The problem can occur right from the moment the iginition is turned on, or the AC may run fine for hours and then suddenly have the problem.

The problem is that the AC stops blowing cold air, and blows ambient temperature air instead. The problem will go away 100% of the time by moving the fan speed control from automatic to manual-high, then back to automatic. Several times I've had to do this twice to make the air cold, but it always works and it is nearly instantaneous.

The ventilation blower runs fine, and the two LEDs on the front panel do *not* flash when the ignition is turned on.

Cycling the AC off and on does not seem to ever make the problem go away.

I'm a little stumped. Any help gratefully received!

Thank you,
Dave

Post by **MadeInJapan** » 20 Aug 2007, 17:34

I had the same thing happen on my S70 last week....checked the A/C gas and I was a bit low....was over 100degrees outside. Added a can of gas and hasn't happened since.

LowEnergyParticle · Post by **LowEnergyParticle** » 20 Aug 2007, 20:30

MadeInJapan wrote:I had the same thing happen on my S70 last week....checked the A/C gas and I was a bit low....was over 100degrees outside. Added a can of gas and hasn't happened since.

Thank you for your response, MadeInJapan! Now that you mention it, I cannot recall the problem ever happening except when it's blazing hot outside. I will check the pressure and see if it is low.

Still, it seems very odd. I have not noticed the compressor cycling frequently, and I still am completely in the dark about why moving the fan control from auto to manual would have the slightest effect!

I will post the results of a pressure test. Thank you again for the reply!

Dave