So if your AC system is completely depressurized then it's likely that moisture is in the system and you really should pull a vacuum on it to vaporize any moisture and pull any air out of the system.

If you don't do this you WILL eventually experience corrosion within the system and damage to the compressor/expansion valves.

Many of the chain auto parts stores have a tool loan program where you leave a deposit and borrow a vacuum pump and gauges for 24 hours. You should look into it.

So, after all that, I'll preface this next part by saying that doing this will override the low pressure protection built into your A/C system and that this shouldn't be done by anyone for any reason.

OK? Here we go.

You're having trouble getting refrigerant into the system because likely the low pressure switch is preventing power to your A/C relay and the compressor clutch isn't engaging.

You can jump your relay socket with a paper clip to get the compressor clutch to engage.

In the engine compartment fuse box look at the diagram on the lid and identify your A/C compressor relay.

When you pull out the relay you'll see a diagram on the side of it.

Look for the switch symbol on the diagram. In most cases it will be pins 30 & 87.

Then look at the bottom of the relay where the pins are. You should see numbers at the base of the pins on the plastic so you can identify the pins.

You'll want to use that to identify which pins are the switch and identify their corresponding sockets on the relay plug.

So get everything ready. A/C switch in the vehicle to ON and Max A/C

Your refrigerant connected and ready to go.

(you don't want to allow the compressor to be running while low on refrigerant longer than necessary)

Jump those 2 sockets with your paper clip.

When the compressor engages you should start seeing refrigerant going into the system.