What are the steps to do this DIY? Thanks

 

look on youtube, there is a few good step by step videos there
this guy is a ford tech
https://www.youtube.com/channel/UCN4...Llk98JddJLL51w
I think this is where I found the best a/c info
https://www.youtube.com/channel/UCT5...uy041dbWPB6skg
this guy is annoying to watch but lots of a/c vids
https://www.youtube.com/user/scottykilmer

 

at the minimum you need a low pressure side gauge.. If your system was working last year, and is "poor" this year, then you are a good candidate for a boost in gas... If your system has a leak or has been out of service for several years, this probably will not work.

Get a low pressure gauge and connect on the low pressure fitting of the system. The cheap way to do this is to buy a gauge / hose that can screw onto a new refrigerant bottle. Might as well have a bottle attached to the hose and gauge.
--When you connect the hose, it will read "about" 80 - 100 psi since the HI and LO sides have equalized in pressure.
--Start the truck and gauge will start dropping as the gas is sucked into the LO side of the pump.. Gauge will go down to "about" 30- 40 psi.
--If the gauge goes lower than 30 psi. or equalization pressure is below 80 psi, then you need to add some gas. Open the valve on the refrigerant can and add about half the can. Stop filling and check pressure again.
--Speed up the motor to cruising rpm ( about 1800 rpm) and see if the pressure stays above 30 psi and compressor runs most of the time. Pump will kick out if pressure drops below 20 psi, or high side goes too high. You will not see that with just a LO gauge.
--Continue to add gas until you have about 40 psi at idle and over 25 psi when at 1800 rpm.
--When the system is working and full, shut off the motor, and uncouple the hose.

---NOTE the pressures are dependent on the ambient temp. You will see the above when it is about 90 degrees outside. I assume you are not trying to FIX the air conditioner when the ambient is 60 degrees. IF you have a low ambient, then the pressures will be different and you can get a chart that corresponds. I use the above when it is 85-90 degrees outside and it is close.

 

I've always had luck with this. Then get the smaller cans as refills
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1