Yes, there may be a fuse inside or outside your fuse box that controls your heater blower motor or another high amp draw electrical component. Most of the separate fuse holders require a 30 amp fuse. You may find a funny looking bent fuse inside your fuse box. Don't just look to see if they have burned out. Kent has sent many that just developed a fine line crack which is very hard to see. Push on the fuse. Look for corrosion. Sold here is a set of two so you will have a spare.
Here you see it located inside a later 126 chassis and it controls the rear window defroster circuit. You just take the flat fuse and bend it at two right angles before installing.