Review the item:
My cat Buster loves to nap on warm appliances when
he sleeps on top of the microwave oven, his tail swipes the glass door like
a windshield wiper.
A comma splice occurs when two complete sentences are incorrectly joined with just a comma. In the example above, no such comma exists. My cat Buster loves to nap on warm appliances is the first sentence. When he sleeps on top of the microwave oven, his tail swipes the glass door ... begins the second sentence.
Because only empty space exists between the two, you should call this error a fused sentence.
To fix the problem above, you could put a period after appliances and begin when with a capital W.