dose any one know anything about air condtioning cycling or have related links with info or any TSB any info?

Question

i am looking for any reliable info on A/C cycling

Answer 1

I'm assuming you know the theory behind what actually makes air conditioning work and won't go into that detail. "Cycling" is merely the turning off and on of the compressor in response to a thermostatically controlled switch on the evaporator (the finned thing under the dash). AC's will create below freezing temperatures and while that's good in a deep freeze full of lamb chops, it's not so good in your car. Here's why. Air conditioning increases comfort by decreasing humidity as well as temperature. Moisture in the air condenses on the evaporator, drips off into a pan with a hose that carries it to the outside of the car. That's what makes the water puddles under a car that had the ac going. For the moisture to drip off of the evaporator, its temperature has to be kept above freezing or else the moisture freezes onto it until it looks like a big snowcone. The thermocouple switch senses when the temperature falls below freezing and shuts the compressor off and when the temp rises iut turns the compressor back on. When the switch fails, the evaporator temp drops below freezing and the first sign is that fog blows out of the dash vents. Soon the moisture has frozen, no air can pass through the evaporator and the ac quits doing what it's supposed to be doing. When that happens, shut the ac off, run the panel vents and shortly the ice will melt and air will begin flowing again. The thermocouple switch will probably be a round disc like affair attached to the end of the evaporator. All I've worked with have a little copper tube that exits the disc and attaches to the fins of the evaporator.