[Qsss]

The rear DC outlet won't work what do I do?

 

[3Wheelerguy]

Have a look at the inside and make sure it is clean. Next step is checking the fuse. After that you will need to check power and ground at the socket by pulling it out.

 

[Shinmai]

The rear DC outlet won't work what do I do?

You've already made sure to turn it on with the switch on dash, so other than that I'd be looking at the fuse box next.