1995 Chevy Truck short

That fuse circuit only goes hot with the key on, according to my info? With the hvac controls turned off and the key off, the fuse still blows?

If the fuse doesn't blow till you turn on the key, unplug the blower relay, then with the key on, hvac controls off, use a testlite across fuse terminals, if the lite comes on, there is probably short on the wiring circuit going to the relay. Instead of hunting the short, I'd probably just replace the wire.