Came out to call. Customer said system just stopped working all of a sudden and couldn’t figure out why. I checked system over and found the system not communicating with the air handler. Inspected air handler and found the 3 amp fuse blown. Put a resetable fuse in and turned power back on. As soon as I did the UVC lamp we installed recently made a strange noise and was putting off a burning smell. Further inspection led me to the internals of the UVC lamp having a short in it, causing the fuse to blow. I replaced the 24 volt UVC lamp under warranty. Seeing that I’m out here, I went ahead and performed the tune up as well. Checked thermostat operation, wiring, capacitor, contactor, compressor, amps, temperatures and pressures. Discussed with customer about about the system being a tad low on refrigerant. Added 1.4 lbs of 410a to get charge correct. System is cooling properly within manufactured specifications at this time.