Most auto repair shops in Tucson use an electronic AC leak detector to find a leak in your AC system. Electronic leak detectors can be expensive. But a DIY AC leak detection kit costs much less than a repair shop charges to find a leak. Most kits use an aerosol can of dye that looks like a caulk gun or fire extinguisher. These kits are great for finding simple leaks in the AC system of cars made after 1994.