Check them both, could be that the radio and blower ground is to the same screw and it is loose and/or not making a good connection.
The fuse box connections could be the problem to, but it is more than likely the ground.
Good luck and let us know what you find.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.