First, go into your underhood fuse block and check MBEC1 50A fuse:
If that fuse is good, pop off the black plastic cover of the relay block. It's located inside, to the left of the brake pedal. Check the 30A circuit breaker on the bottom left:
If either one keeps blowing, then you probably need to systematically chase down a short, which could be at the wiring underneath the carpet, or at either of the seats themselves.
You could try unplugging each seat separately to see if the short goes away. If the fuse and/or breaker still blows with both seats unplugged, you may have to pull back the carpet and look for an exposed wire.