General Motors vehicles are now manufactured with fluorescent dye installed directly into the air conditioning (A/C) system. The fluorescent dye mixes and flows with the polyalkylene glycol (PAG) oil throughout the refrigerant system.
Verifying some passive leaks may require using Special Tool J 39400-A Halogen Leak Detector, even though the A/C system contains fluorescent dye. The only time that adding additional fluorescent dye is required would be after flushing the A/C system.
Follows any instruction supplied with a universal leak detection lamp. Leaks in the A/C system will be indicated in a light green or yellow color when using the lamp.
Use the leak detection lamp in the following areas:
All fittings or connections that use seal washers or O-rings