Also this is the 15 amp fuse that's popping? If so diagrams I'm seeing show that off the radio fuse is the radio, the cigar lighter, the low washer fluid level switch, and interior vanity lamps. At least that's for the switched power to the radio.
If you are talking about the 87 fuse box, Renix, the fuse that runs the windshield wipers, cigarette lighter and AC Blower, and the turn signals, it is a 25 amp fuse, not a 15 amp fuse, and even the 25 amp fuse and the wires from the fuse box to the ignition switch, ignition switch guts and AC blower are undersized and known to melt and short at the ignition switch and the blower switch. They could be the real problem. But if the radio is dead and the AC blower works, something very odd is going on, did someone rewire the entire jeep?
Also this is the 15 amp fuse that's popping? If so diagrams I'm seeing show that off the radio fuse is the radio, the cigar lighter, the low washer fluid level switch, and interior vanity lamps. At least that's for the switched power to the radio.
Where is this radio fuse at? The OEM wiring on an 87 Renix has one main fuse in the box that powers the radio and blower and wipers and electric door locks and windows (if you have them). If it is an aftermarket radio fuse/wire then that wire is shorting to ground somewhere on its way to the radio.
Blew a Motor? The engine or ventilation blower motor?