A/C system question

I recently purchased a 91 Nissan hard body pickup with 138k miles...it's a great little truck for an even better price. The A/C isn't working and the previous owner says that it worked great until he let the truck sit for a pretty long while as he no longer used the vehicle. My question is if the issue is just that the Freon leaked out of the system shouldn

Can you hear the blower spinning inside the blower box? The motor could be bad since its an old truck Just turn on ur ac and put ur hand on the blower box to see if you feel it spinning

you can turn your heat on and if you feel it blowing, then the blower motor is working.. turn your AC on and pop the hood.. look at the AC compressor and see if its locking and unlocking.. if you dont see it lock down when it clicks, or it never clicks, then the clutch is most likely bad..

my mechanic friend told me that if there's not enough Freon in the A/C system then the compressor will not kick on. I'm fairly confident that it's simply too low on Freon. My buddy is going to pressure test it next week. Until then...