Came out to call. Customer stated that the system stopped working all of a sudden and was only blowing cold air. The heat pump wouldn’t work, nor was the auxiliary heat. I checked system over and found a blown low voltage fuse. The last time this happened it was due to the 24 volt uv lamp. I checked the lamp and found it to be the culprit again. I’ve already replaced it under warranty before, but we have a newer model now. Told customer I would have to come back out to replace it under warranty again. Customer stated that it’s not an emergency, and can be done on his next service.