If that doesn't work you need a set of gauges on it. Look at the low side pressure when the compressor is engaged. The pressure will drop when the compressor engages. If it drops to about 20lbs the compressor will disengage due to low pressure. I.E. you need more refridgerant. I charge all mine to roughly 40lbs.

If the pressure is good on the low side the you need to look at the high side.
Things are not always straight forward at this point but... If the pressures are both about the same pressure the compressor may be done or something is plugged. Let us know what you see of it gets this far.

 

ok thanks. ill start troubleshooting maybe later today after work or tomorrow. I have a test gauge but where is the low pressure valve at. I see the high pressure one

 

which pressure switch tho

 

Its the low pressure cut off switch. The low pressure port is on the accumulator ( the large metal can). Always fill from the low side port!

 

alright thanks. I still haven't had the time to do anything but ill keep you guys posted