The fan in my 1996 Riviera won't blow. Fuse looks ok. Jumper directly to a battery and it blows full speed. Anybody have any ideas?

Most likely your blower control module has failed. Follow the wires from the blower motor back toward the firewall. They attach to this module which is actually inside the vent. Two screws and you can pull it out. Easier if the blower is taken off first.