I bought a 04-TL recently, it has 45k miles on it. The car is clean and drives pretty good however i have noticed that the AC compressor cyles every 30 seconds, is that usual ??

 

is your AC on?

 

It's completely normal when the AC is on. Don't forget, AC is on when you have it in defrost.

 

It would depend on the load on the A/C. If first started in hot, humid weather, the compressor shouldn't cycle on and off every 30 seconds, but on a balmy day when temps aren't high, might ne fine. Next hot/humid day, set the temp low, start the car and see how the compressor operates, and temperature of the air coming out the vents.

 

The compressor cycles only when the ac is on and irrespective of the weather it cycles every 30 seconds.The temp of the air coming from the vent is cool if i set the temp low and it is warm/hot if i set a higher temp(70+)

 

Air from the vents can feel cool when the weather is hot and humid, but it's not an indication of proper system function. In hot and humid conditions the compressor will run longer cycles to cool down the cabin, but once cool it will cycle. Too many variables to contend with, but if you want to check the system, purchase a stick thermometer and put it in the center vent to see the delivery temp, then that can be compared to the ambient air temp and humidity level at time of test.
Example:
http://www.amazon.com/Interdynamics-.../dp/B0007ZAJDQ