The AC in my 87' F-250 isnt working, i just bought the truck and dont know where to start, i am not very experienced here, if anyone could help that would be great, thanks.

 

Best bet is to get a set of gauges and determine how much if any charge of freon you have in the system. With the system not running the system pressure should read about 100 psi + or - based on ambient air temperature. Depending on the amount of freon in the system the compressor may not come on because of too low of pressure. If you have at least 30 psi the compressor should cycle when the engine is running and the AC system on. If not then you need to check the compressor 12v circuit. To do this you will need a wiring diagram showing fuses,relays and switches in that circuit that could be not working. An initial test for seeing if the system is low on freon causing the compressor to not run, is to jumper the pressure switch at the accumulator drier and with system on AC and the engine running see if the compressor engages. If it does then low freon is probably your problem. Don't run the compressor any longer than to determine if it will engage since loe freon pressure will not cause AC refrigerant oil to flow and adequately lube the compresor. Again, you really need gauges to properly check and charge an AC system. Also, you need to know what freon is in the truck R-12 or R-134A. In 86 R-12 is what was used but the system may have been converted. You cannot mix freon types.

John