its now empty no freon ( R-12 )

im going to fill it this afternoon will it turn on then?? becuase i tought it wont turn on when its empty...

or is it something else? thanks!

 

If it is empty it will not turn on..When you recharge, it will see the pressure and start to cycle rapidly, as it gets closer to capacity, it will cycle more normally.

This is assuming everything is in working order (other than the freon level, that is) and connected properly.

If you have to, you can jump the switch connection (2 wire switch connection, looks kind of like a oil pressure switch for a light, not a gauge) to give it a jump start, but I don't recommend running it it like that much. It won't run when empty for a reason..if you bypass that reason, you will cook your compressor.

 

ok.. i think it should be fine then.. it was turning on few months ago... i messed with it let the little freon it had in it left and it didnt turn on anymore thanks..

 

The pressure switch is located on your condensor. Two wires fed into a wire connector. Unplug the sensor and use a piece of wire to jump it. Start the truck up and turn the ac to normal. If the compressor kicks on then you need to service your system. If it doesn't kick on you will want to check power to the compressor.

 

There's also this:

E1AZ19B888B .. A/C Vacuum Control Selector Valve Assy (Motorcraft YH380)

(Fits: 1990/91 F150/350, Super Duty & Bronco / 1981/91 Crown Vic/Mercury Grand Marquis = all with factory Integral A/C)

MSRP: $21.58 / ftepartsguy.com price: $12.43

This valve is mounted to the backside of the A/C heater control panel.

This particular valve has 7 nipples on it that the vacuum lines connect to.

It also has the "kicker switch" on it for the A/C compressor.

When the lever is moved to A/C, an audible click is heard...when this switch works.

Tens of 1000's of these valves have been sold since the late 1960's, mainly because that &^*^#^&% switch failed.

 

ok good news.. it does kick on when i jumped the condensor pressure switch like you said..

so now i know it only needs Freon right???

 

Go ahead and charge it and see if it holds for a while. I don't know anywhere were you can get R12 legally but you might try and find some Freeze-12. Only catch is some places say you have to have a HVAC license to buy the stuff (such as my state for an odd reason). Just my .02 cents.

 

ok i will charge it and see if it holds ill post back.
i dont live in the states.. where i live i can get R12 anywhere.. i just went out and bought 3 cans of it..

3 cans of 12 OZ ( 340G.) they said that will be enough.

 

Electrical plays a big part in the AC system. What Number Dummy is talking about is great advice, and when it comes to AC, this is the first thing I forget to do! Check to see if indeed the switch he's talking about is working and that the electrical side of things is functioning. As you know, a perfectly charged AC system won't work unless something tells the compressor to turn on!

If the electrical side of things works ok, there's a couple of quick things you can check. Anytime a system runs low on freon, it has a leak. Period. Take a look at the AC condensor. Look for wet or oily spots on the condensor. If so, there's not much point to charging the system, as it will only loose the new freon you put into it. Take a look at your AC lines.... especially where the rubber meets the metal fittings. Look for "soft" spots or excessive dampness there. If your truck is anything like mine, the engine compartment isn't exactly clean, but you'r looking for drops of oil or very wet dirt! Also, take a look at the accumulator / reciever dryer. This is the big black can-like thing located by the blower fan motor under your hood (I'm assuming your truck has factory AC). Check for leakage by the cut off swich there. These leak frequently and can be changed without breaking the system. Find the other cut of switch where Zamboafood said it was located and check for excessive dampness there too.

If you can't find anything, I'd charge the darn thing. If you do find something, then it's time to replace the component that's leaking. You're supposed to recover the R-12 before you break the system I'll leave that decision to you. Once you've broken the system and replaced the bad parts, I'd also recommend changing all of the schrader valves. There are three if I'm not mistaken. One in the high port, one in the low port and one in the accumulator where the first pressure cut off switch is. You will need to have the system evacuated at this point. You can not just charge a system that's been broken as water vapor in the air that is present within the system will mix with the R-12 and cause a corrosive mix that will cause you grief in the future. An AC shop shouldn't charge you much to evacuate the system. Once it's evacuated, you can take the truck home and charge it yourself with the R-12 you bought.

Oh yea, I forgot. BChance made a really good point too. Don't fart around with jumping the pressure switch too much. It's a great test, but once you've assured yourself that the compressor is engaging, running a system that's low on Freon can really wreck things in a hurry.