As I drive down the road the a/c cycles on and off about every three seconds. I shorted out the low pressure cut off switch on the filter dryer and the problem is still there. I suspect it might be the evaporation thermal switch but I hate to pull out the evaporator to check this. Has anybody had similar issues. 96 legacy 2.5. Also if I turn the blower on high and roll down the windows it seems to real help the problem. I have also checked 134a pressures and everything seems to be normal.

If you're sitting there idle, does the compressor cycle on and off? Or does it only do it when you're driving?

Also short cycles at idle, but the cycle time is alot longer. Maybe around 30 seconds. pressures seem stable while at idle. (Not kicking out on high pressure). I have not shorted out the high pressure switch yet. I will try that tommorrow.

I had a similar issue on my 97 Legacy. More than likely, your AC system is overcharged. Once I bled some pressure off, it went back to normal.

The high-pressure cutoff occurs at about 400 psi. Was any AC work done before?

What were the pressures you were seeing, and what was the ambient temperature when you took those readings?