David and group, There are several thing which affect the cycling of the A/C compressor. #1. Is the Low pressure switch. Condition and adjustment. #2. Amount of freon is the most common because you may tend to leak down during the winter. #3. The amount of air blowing over the evaporator core in the heater box compartment. #4. The Temperature of the air blowing over the evaporator core from out side. #5. The compressor will cycle more if the speed of the blower motor is set on 1 vs 4. #6. The temperature outside. Slower speed the more cycling. It's like a clock working, it all depends on the conditions of all. If the LP switch is ok, and your full on freon,and it's 80 to 90 degrees out side and you have the blower motor set on 4. Then mine cycle about every 40 sec. But, If your low on freon, and the switch isn't adjusted correct, it's 70 degrees out side and you have the blower fan on 2, then you may cycle every 5 sec. What's happening is the LP switch is trying to protect the compressor from freezeing up by cycling the compressor on and off. John Hervey www.specialTauto.com P.S.There is a good technical explaination on page 334 of the technical manual. --- In dmcnews@xxxx, Delorean17@xxxx wrote: > Hi, > Before I go to Memphis I want to make sure I am not going to fry my AC > compressor on the way. I had the system vacuumed out and charged with R12 > last summer and it has been blowing cold air ever since but I think it may be > cycling a bit much. > I have a light hooked up that shows when the AC compressor comes on. > When driving 45+MPH the AC compressor comes on for 2 seconds, then shuts off > for 3-4 seconds then comes on for 2 seconds again, and over and over. > Doesn't that seems a little excessive? How can it be fixed? Can this be > adjusted? > > Thank you > > David > 6286