AC doesn't blow cold air on 95 4 runner. Can I check compressor

First thing is to check and see if there is a belt in tact on your compressor and then see whether or not the compressor clutch engages (clutch is on front of compressor in front of belt.) If so and no cold air, u may need to charge it with 134a refrigerant or have a leak that you'll probably want a shop to repair. Good luck and hope you stay cool.

Make sure your blower fan is turned on and is blowing air. When you push your a/c button the yellow light should come on. If it is not blowing cool, it could be several things. Low on 134a or the control that has the a/c button on it could be bad or blown fuse, bad compressor, etc. If the air is cool but not cold the 134A is low. If it is still blowing hot, check and make sure that the clutch on the compressor is locked in. It most likely is not. Check ac fuses and ac relay, if they are good, check the 134a ,if low, refill it. This should fix it. Remember that if the a/c clutch is not locking in, you cannot add 134a because of no circulation.On some vehicles, if it is completely out of 134a, the relay will not trip and you will have to bypass the relay to provide power to the compressor to fill it. If you do all of these and it still does not work, you will need to take it to a professional. If you need to, reply back and I will give you more possibilities.(I think that you mean evaporator coil)

A mechanic would check the system with a set of pressure gauges. If the compressor is running, the low side would read around 30psi and the high side would be around 250psi. That is how you know if the system is full of freon or not.
You may have to get a professional diagnosis to proceed. If you replace the compressor, the accumulator needs to be replaced and a vac pump is used to pull all of the air out before the freon is added.

CHECK THE AC AND HEATER CONTROL FUSE.MORE LIKELY FUSE BLOWED BECAUSE AC COMPRESSOR COULD HAVE FAILED IF LOW SIDE IS OVER 100 PSI. THE REED VALVE PLATE IN COMPRESSOR PROBABLY DAMAGED CAUSED COMPRESSOR FAILURE BLOWED THE HVAC CONTROLS FUSE. HAVE AC SHOP CHECK IT OUT.

HIGH PRESSURE CUTOFF SWITCH LOCATED ON AC COMPRESSOR DISCHARGE LINE LEADING TO THE CONDENSOR.THE HIGH PRESSURE CUTOFF SWITCH WILL CUT OFF THE AC COMPRESSOR IF SYSTEM PRESSURE RISES TO HIGH CAUSED BY RESTRICTION IN THE REFRIGERANT CIRCUIT OR OVERHEATED CONDENSOR.MAKE SURE COOLING FAN IS RUNNING WHEN THE AC SWITCH IS ON.THE COOLING FAN KEEP CONDENSOR COOL, IF COOLING FAN DONT RUN.YOUR AC WILL STOP BLOWING COLD AIR.HAVE THE REFRIGERANT SYSTEM CHECK OUT.MAKE SURE YOUR LOW SIDE PRESSURE IS 10 - 37 PSI. THE HIGH SIDE PRESSURE SHOULD BE 112 - 210 PSI. CHECK THE AC COMPRESSOR CLUTCH FUSE AND RELAY.

Check if the compressor is working.
looks like there is a problem with compressor , hence working intermittently.

This is most likely the cycling of the AC unit. As the compressor pressurizes the 134a Freon you get the cold air, once it reaches a certain pressure it cuts out. If you are low on Freon it will cycle out more often. Check your freon level with a gauge to see if your within the proper tolerance. If the compressor runs for a period and doesn't reach the right pressure it will cut out to keep from damaging your compressor so it is important to keep the correct amount of freon in the system.

Apart from doing a low side pressure check, you can try to recharge the system yourself with a refill kit that's readily available at most auto parts stores. If you're concerned about a leak, also get a can of R-134A with the UV dye that will show any leaking components.
RECHARGING AC SYSTEM

1. Turn the truck on and turn AC on HIGH
2. Locate the low side AC line (will have a valve and cap similar to the cap on a tire)
3. Insert the oil or R-134A can to the hose (Do not turn the screw to puncture the can yet)
4. Insert the other end of the refill hose to the low side valve
5. Puncture the R-134A can with the screw on the refill hose
6. You should feel the system suction the refrigerant out of the can
7. Check for frost on the AC lines and the air blowing inside the truck
8. If frost develops and the air is cold, you've successfully recharged the system and disconnect the refill hose. DO NOT ADD MORE REFRIGERANT...overcharging the system will damage your compressor and will be less effective

Hopefully this answers your question and you're able to get your AC working again. Best of luck.
Greg

Your AC is low on refrigerant; The AC compressor needs a minimum amount of regrigerant to run. If and when it does run (while low on refrigerant) the air coming out of the vents will not be cold. The refrigerant you require is R-134A and is available over the counter but if you are the least bit unsure as to how to add refrigerant, taking it to a garage that does AC recharging would be your best play. If you want to try to add refrigerant on your own you will need the following, 1LB can of R-134A, an AC hose adapter to deliver the refrigerant, and preferably an AC pressure guage to ensure you are not overfilling the AC line which will damage the system.

HI, giving the compressor 12v directly is not the way to go as you are bypassing the entire fail safe cercuit. it seem to me that your ac gas is low(can be checked via ac pressure gauges) wich means you have a system leak sumwhere. as soon as your hi/low pressure switch(depending on system) detect inferior pressure to the spesified pressure ,the ac compressor voltage is cut in order to protect the pump from seizure.

Or perhaps your evaporator(small radiator like unit behind dash) can get freezed up caused by either too mutch system gas(check pressure) or poor opperation of the expantion valve. the evaporator then has a sensor(themometer) wich measures evap. temp and if the value drops below spec (usially round about7degrees) the ac compressor will be cut once again(fail safe)

Maybe your ac compressor overheats due to inferior system oil/oil capasity, also note that only some systems incorperate the function of measuring ac pump temp. then again temp to high= fail safe=no12v to ac pump.

Good luck.
gk