My seat buttons and rear defroster operate sometimes, other not. What could cause this?

 

Those are both protected by the same 30 amp circuit breaker (fuse panel position 12). I would guess that the circuit breaker is the source of the problem, especially since it would be 23 years old now. You can confirm by replacing the circuit breaker with a 30A fuse and see if the intermittent problem goes away. Then you can decide whether to replace the circuit breaker or just leave the fuse in place.

 

What is the pn for the 30a breaker. It has spades not pins

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They are standard ATC / ATO circuit breakers available at any auto parts store or online.

ATC and ATO are different designations for what is essentially the same fuse. ATO (Auto Thermal Open) fuses are open at the bottom exposing the fuse element to the air for a little better cooling while ATC (Auto Thermal Closed) fuses are enclosed for corrosion protection, but they are the same size with the same spade terminals and are interchangeable for all interior automotive applications.