I have a 2000 TL, the AC compressor turns on and off, on and off, so the car never gets cool inside. It seems to do it more on hotter days. I just filled the r134a, the gauge reads right in the middle of full.
Any ideas??

 

Mine was doing same thing even though I had Refrigerant in it...
I took to my mechanic bro and had it completely sucked out and new stuff put in, the CORRECT amount, it now spits out 38 degrees even with Turbo heat
It's quite possible that the compressor is bad if the level of the charge is sufficient, but I highly doubt it... I have a rigged on A/C compressor and it's been thrashed so many times and it still works perfect, (maybe a little noisy, but who cares when the windows are up )
I think my prob was too much charge, or more importantly too much OIL, which is prob your prob too...
We put it on the A/C machine and watched the pressures, it would rise TOO high like 400psi on the Hot side, so the computer turned it off so it won't blow the compressor.
It would turn on then turn off like almost immediately.
just get it cleaned and new stuff in at a SHOP, not yourself, and it should work perfect.
Hope this helps,
Later,
Mike

 

You say the gauge reads 'right in the middle of full', but that sounds too simple. You should have to look up what pressure it's supposed to be, based on the outside temperature. Then have it running, & measure while the compressor is engaged.

I think that quick cycling can be caused by over-charging, or also by a plugged expansion valve. Do you have a gauge set that measures both high & low side pressures?