Breaker or fuse for 12 volt plug?

12v uses fuses. should be right next to AC breakers

Examine automotive 12 volt fuses carefully. They can look OK with just a quick glance.

bob213 is correct.
Also, sometimes single circuits have a simple in-line fuse.
Similar to this....

If you're unlucky in it not being the fuse, there's always the chance it's a bad connection somewhere. A bad connection may or may not be hard to find. If not a fuse, perhaps start by pulling the wall plate off and use a voltmeter to see if there's 12 volts at the wall plate. Suppose it could be a bad wall outlet/plate too. I've had loose wires at crimp connections including one where the wire fell right out when touched.

Great, I didn't see any fuses initially by the breakers but I'll check closer and go from there.
Thanks!

Found it, the 12V fuse box was in a totally different location. The 7.5 amp fuse blown. Thanks.