I have a 2001 jetta ac clutch not engaging freon pressure levels read good by pass compressor its cools good.

Hard to say with just low pressure readings. But either the high pressure switch is bad or you are low on freon. If you want to know what is wrong I need the temperature of outside air, the low pressure reading and the high pressure reading as the compressor is running. But this only tells you ta particular problem. It won't tell you if you have a leak. This you have to find out on your own.

Just because the clutch is engaging does not mean it has enough freon to make it cold. I would want to know what the high and low pressure gauge readings are. It may need a can or two.

Depending on how much freon is in the system, it could be a faulty low pressure switch or a faulty clutch.
You would jumper the low pressure switch to eliminate it for a test.

try to throw cool water on the condencer front of the engine radiator and see whether any cool air comes in the car. If so see whether the pressure valve is working okey or not because might the pressure is not sufficient.

I passed this question the first time I read it, so I will take a stab at it now.
The fans don't come on until the compressor has pumped the freon pressure up to say 150 or 200 psi. And the compressor clutch has to have voltage to engage the clutch.
I wonder if the clutch is going and needs 14 volts instead of 12 to engage ? Or the relay that powers the clutch ?
Speeding up the engine would increase voltage from the alternator.
This is assuming the serpentine belt is tight and everything else is working correctly.
I think I would swap the relay with another and put a meter on that circuit to the ac clutch to see what it takes to engage it.

Ac compressor clutches get power from a relay via pressure switches.
If the system is low on freon, the low pressure switch prevents the ac clutch from engaging.
The clutch is a magnet.

The most common cause of no clutch engagement is a low state of refrigerant charge in the system. Have a set of AC pressure gauges hooked up and bypass the compressor cycling switch and check the pressure on the low side charging port, you show shop 28-32 PSI at idle.

The pulley on the compressor is always running when your engine is running, but the only time
it compresses the freon is when the clutch engages, if the compressor's pulley was not turning,
it would have already snapped a fan belt or your serpentine belt. voltage runs from your fuse box
thru your air condition switch on your dashboard to a low pressure switch that is located at the
accumulator a long cylinder,close to the firewall under the hood or close to the condensor, front
of the car. the switch detects freon pressure in the accumulator, if there is freon pressure, the switch
will stay closed and allow voltage to go to the compressor clutch to engage it and compress the freon,
if there is no freon pressure the switch will open, and there will be no voltage to air compressor, its a
saftey switch to keep your compressor from getting damaged.its possible that the switch could be bad
it may not have voltage at the switch, or it may be open because there is insufficient freon pressure.
check and make sure there is freon in the system.check for voltage at the low pressure switch if you have freon in your system and voltage at the pressure switch, set your ac on high, pull the molex off
the switch, and jump it out with a jumper wire, if the clutch engages and your car starts to cool, just
replace the switch. if the clutch engages but does not cool, then your ac system has some blockage
in the lines. if the clutch does not engage at all then it would be the compressor clutch. good luck!

The A/C system has a pressure sensor that detects the freon level in the system. If you lost freon, the clutch that engages the compressor will not engage. A good indicator is to turn on the A/C and watch the compressor/clutch assembly. If the pulley is spinning and the clutch is not, odds are you have a freon leak. Good luck!!

You must of lost freon and when there is no freon your clutch will not activate.Must check it for pressure in the lines.If there is pressure check pressure switch.Good luck let me know