God answers prayers. My solar sensor is working again!
With the light of day I decided to get a closer look at the solar sensor and cable. Turned out the cable was compressed between the main mast and an aluminum beacon holder. I'm not sure what was happening. (Probably EMF phenomena. Anyways, freed the cable and waited until after sunset and sure enough the solar radiation dropped to 0. I don't have to spend 137$ for a new sensor!
Thank God!