I drive all day in my truck, (93 3.0)
With the temperatures here in sunny Southern California hovering in the high 90's to low 100's, I'm using the Air almost all day.
It worked fine for the first 4 hours of my day.
It also worked for the later 4 hours of the day.
However in the middle of the day there was an hour where it stopped putting out cold air and put out lukewarm air. it was about 100 degrees outside so this represents a real problem.

Has anyone else had this problem of the A/C system taking an hour off?

Do i have a component problem or just need to re-charge?

 

Was the compressor running, or not?

 

The little yellow light was on, A/C button pushed on.

how would i know if the compressor was actually running?

 

Open the hood and look down at the a/c compressor. if it's not running, the pulley will be free-wheeling on the clutch. if it is running the whole shaft will be spinning as well.
If you look behind the grill, you should see the accumulator- a small, vertically-mounted cylinder with two hard pipes going into it, one on each side, and it might have a small, circular 'sight glass' or window in the top. If it has the sight glass you should see what looks like fluid moving through it when the compressor is running.
You can also check the refrigerant lines that go through the firewall- one should be cold to the touch and the other quite hot if the compressor is running.

There is the chance that the a/c needs charged. It has a pressure cut-off circuit that shuts the a/c off when the pressure in the system is not proper. The combination of high ambient air temp and low refrigerant can cause the switch to be triggered thus shutting off the a/c.

Do you know if the system r-12 or r-134a?