AC was not blowing super cold and compressor was cycling on/off with very regular frequency (engaged for 3 seconds, off for 3 seconds, repeat). Recharged system assuming low pressure sensor was causing kickouts. AC now ice cold when compressor is running, but still cycles on/off when auto temp is on lowest setting and/or fan set to high cool. Air warms up noticeably when driving and compressor not engaged.

Checked fault codes, found 2-2-1 Pass side damper motor position sensor short to ground, 4-1-1 Blower fan seized or drawing excessive current, and 4-1-7 Pass side interior temp inlet fan seized.

Reset fault codes and they haven't come back. Checked both side inlet temp sensors. Both sensors dirty and dusty, blew out, cleaned both sides and made sure fans spin freely. No more fault codes, but compressor cycling problem still exists.

What else can I check or what else could cause regular cycling of the compressor? The cycling happens in both auto and manual mode and doesn't appear to be tied to any particular driving style/events. What other sensors/electrical items trigger the compressor clutch to turn on/off? My Clymer book has schematics for every electrical system except the A/C / Auto Climate Control!!

Is there a simple way to jump the compressor clutch into the 'on' position for the summer months?

The 850 uses a CCOT A/C system, i.e. Constant Cycling Orifice Tube controlled gas system. The compressor cycling should be more like 30 seconds on, 10 seconds off type but not 3-on/3-off. Have you put a pressure gauge on the low side line to see what its pulling the pressure down to when the compressor runs? You want it between 25-30 psi on the low side (with the compressor ON), it will jump up to 50-60 psi with the compressor OFF. I would recommend hooking up the gauge to it and note what the pressure is actually doing. If it pulls it below 25 psi quick and easy I would say add a little R134 until it stabilizes between 25-30 psi at idle. Don't "Hot Wire" the compressor to run all the time or you'll end up with a seized compressor in short order. If you over pressurize the system (add way too much freon) the high pressure switch will shut off the compressor prematurely. Good luck......... Mike

Thanks, I'll do that tonight. Appreciate the input.

I agree completely...sounds like you have enough gas to cool but still not the correct amount. The kits with guages can be bought at places like autozone. Make sure you follow instructions and add the refridgerant oil too if indicated.

How would you know if adding oil is indicated?