For those of you worried about using compressed air because of moisture. My question to you is, what do you think is in a system that has a leak and all of the refrigerant is gone? Atmospheric air and moisture! This is a tried and proven test for me over the last 25 years and it is one that everyone can do. Who has a bottle of compressed nitrogen sitting around anyway, especially when you only do a few A/C jobs a year. Tools used - A/C Manifold Gauge Set https://www.jbtoolsales.com/atd-tools-3695-deluxe-dual-aluminum-a-c-manifold-gauge-set#oid=1014_1 - Vacuum Pump & Gauge Set Assortment (least expensive kit I could find that I felt was descent and it is the one I use) https://www.jbtoolsales.com/fjc-9281-vacuum-pump-gauge-set-assortment#oid=1014_1 - 3.0 CFM Vacuum Pump (same pump that comes in the kits listed above) https://www.jbtoolsales.com/fjc-6909-3-0-cfm-vacuum-pump#oid=1014_1 - 6 Gallon Air Compressor 150PSI https://www.jbtoolsales.com/bostitch-btfp02012-6-gallon-air-compressor-150psi#oid=1014_1 - Spray Bottle W/Sprayer https://www.jbtoolsales.com/meguiars-m9911-spray-bottle-w-sprayer#oid=1014_1 Car Wash 64 oz https://www.jbtoolsales.com/mothers-05664-california-gold-car-wash-64-oz#oid=1014_1 - R-134a Can Tap Valve https://www.jbtoolsales.com/mastercool-85510-r-134a-can-tap-valve#oid=1014_1 - Bayco NSR-2168B LED Rechargeable Work Light - 600 Lumens w/3 Magnets Lithium-ion Battery https://www.jbtoolsales.com/bayco-nsr-2168b-led-rechargeable-work-light-600-lumens-w-3-magnets#oid=1014_1 Related videos - HVAC and Cooling systems troubleshooting and repair    • A/C and Cooling System Diagnosis and ...   - A/C clutch not engaging - 2005 Honda Odyssey https://www.youtube.com/watch?v=KTbmgjA0N9s - A/C Leak Testing and Repair part 1 - 95 Jeep https://www.youtube.com/watch?v=jTAfYJyPniM - - A/C Leak Testing and Repair part 2 - 95 Jeep https://www.youtube.com/watch?v=JSCnjcQm-ZQ - A/C Leak Testing and Repair part 3 - 95 Jeep https://www.youtube.com/watch?v=FIyuiNV-82s - Air Conditioning Not Working (system performance, leak test) - Honda https://www.youtube.com/watch?v=m5XM5Ak55gU For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book. Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium https://www.scannerdanner.com/join-scannerdanner-premium.html There is a 14 day free trial. On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere! Disclaimer: Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC.