Both my 95 Imprezas and my 95 Legacy all don't seem to allow the compressor to cycle on and off in cold weather. If I select defrost, the compressor turns on to decrease moisture and fogging, but when it's below 50 it seems that they cycle on for about 3 secs and then rarely turn back on. This doesn't allow defogging to be effective.

 

All these car's A/Cs operate VERY well in the summer.

 

Is there a temp sensor, or is it just that the evap sensor gets cold fast and cycles the compressor off? I'm confused.

 

Thanks, Todd

My 97 impreza does that too....it wasn't defogging worth a crap this morning.

 

I have not checked the pressures on the system, but I suspect once a critical temperature is reached the temperature sensor in the evaporator core will turn off the compressor until the evap core temp rises. You will still get some moisture condensing, but I agree it won't be as effective. However....if it didn't do this, the evap core would probably freeze up.

 

If I get around to it, I'll check the pressures on the impreza & post back.

 

The first gen legacies had a wobble compressor that varied geometry, and therefore didn't need to cycle. Good in theory, however they will eventually fail. I'm on my 4th one....and decided to buy a brand new one from the dealer since the other used ones died.

Thanks for the feedback.

 

What is the correct charge in these systems. (134A) oz wise? 24oz?

 

Tell me what your pressures are and I'll compare that to mine.

 

Todd

I'm not sure what the charge is. I'll have to look at the sticker on the car, and compare it to the Haynes AC book I have.

What was the temperiture outside. Usually (some are higher some are lower) below 35 they dont run, as the air is do dry that there is no humidity to remove.

 

nipper

It was high 30s I think. It worked well today at 62.

It was probably too cold for the AC to come on.

 

nipper