1995 Devile A/C Recharge

I got a message on my display that says "A/C Compressor Off / Pressure Very Low" or something similar.

I bought a recharge kit but how do I get the compressor to turn back on so I can refill it?

I tried disconnecting the negative battery cable but that didn't help, message immediately came back.

The Haynes manual says to jumper the "Low Pressure Switch" but I'm not sure where that is.

Can anyone help?

If you get an intial charge into the system the compressor will come on. But this is not he way to fix this how do you know it is low, if so where did it go? The system should be evacuated and drawn down to see if it holds vacuum, partially charged and properly leak tested.

If you get an intial charge into the system the compressor will come on. But this is not he way to fix this how do you know it is low

It appeared on my display.

if so where did it go?

I don't know where it went. I assumed it just needed to be recharged.

The system should be evacuated and drawn down to see if it holds vacuum, partially charged and properly leak tested.

All I want to do is add refrigerant. I don't have the time or money right now to have it serviced. I bought a rechage kit and I don't want to waste the refrigerant, especially the can that's already opened. If there is a leak I will have that dealt with later.

The A/C has been working fine up until yesterday. It's been over 100 degrees for a month here so I really didn't question that it might be low on refrigerant. I got the car from my mother only a couple of months ago and as far as I know she has had it serviced regularly.

What MW said is, of course, the correct procedure.
However, for a possible quick and dirty fix you might first try unplugging then reconnecting the sensors along the AC lines. A dirty connection can give you a bogus code. BTDT.
Second, clear the codes through the comp using the DIC or disconnecting the battery for a minute. With the engine off, hook up the AC recharge kit and open the valve. Start the car. It should pull enough out of the can so that the compressor stays running to accept the charge. BTDT too.
FWIW
YMMV

What MW said is, of course, the correct procedure.

I will have it fully checked out ASAP.

However, for a possible quick and dirty fix you might first try unplugging then reconnecting the sensors along the AC lines. A dirty connection can give you a bogus code.

I only found one sensor on an A/C line going from the compressor towards the firewall, I thought maybe that was the low pressure sensor, is that right? There were a couple more on some smaller lines going across the firewall, are those AC sensors too? They are a little smaller than the first one. I looked at the contacts and they didn't appear dirty but I'll spray some no-residue electronics cleaner in there to be sure.

BTDT.

I'm sorry, what does BTDT mean?

Second, clear the codes through the comp using the DIC or disconnecting the battery for a minute.

I disconnected the negative battery cable for a few seconds, I'm guessing that's not long enough? My radio station presets were still there so I'm guessing no.

With the engine off,

Ah, that's what I was doing wrong...

hook up the AC recharge kit and open the valve. Start the car. It should pull enough out of the can so that the compressor stays running to accept the charge. BTDT too.
FWIW
YMMV

OK, I understood FWIW... BTDT? YMMV?

Thanks for the advice.

Update: I cleared the codes via the CCC and and it took almost a whole can of refrigerant.

Next step... find out where it went.

Thanks for the help.

Sounds like you may have a leak.
BTDT = Been there, done that
YMMV = Your mileage may vary ...means it may not work for you

I see.

I guess it has to be going somewhere, but it's a very slow leak. Hopefully It won't get worse before I can find it and fix it.