[69 Limelight]

Correct on cycling. Has an evaporator temperature sensing bulb that is mounted on evaporator outlet line next to expansion valve temperature sensing bulb. When evaporator gets to low temperature preset temperature switch cycles compressor off when evaporator warms to preset temperature switch cycles compressor back on. The temperature range is very narrow so no wild outlet vent temperature swings like you get with the POA valve replacement that has been on market quite a few years and cycles based on pressure. I didn't install until late summer (like September) and ambientes were mid to high 80's but worked great with outlet vent temps in mid to high 30's (using R-12). Some people say AC A-6 clutch won't last cycling. IDK as I have a Pro6Ten compressor that has much less "pull" on engine than AC A-6. No you do not have to split evaporator case to install either expansion valve or Old Air Products "POA Deluxe Update" but unless you're sure evaporator core is clean, might be good idea. P.S. The temp switch that comes in kit may be somewhat adjustable as to cycling on/off temps as it has a piece of tape on switch housing that I suspect has access hole to adjustment screw IDK as I didn't remove tape to see what was underneath and it worked fine for me. I was going to call Old Air Products and ask but, never did. Good luck.