2001 Ford F-150 cig. Port and ACC. Port. Short or blows fuse

State inspection, inspector plugs his dba cord into your trucks system under dash, name of the plugor cord I dont know the correct term. Used? But when I plug a 20a fuse in the #3 spot in fuse panel and it pops time again. Of the two power outlets one works, the left side I belive it works the cig lighter, I use it daily a radar detecter. My question is there a right way of taken out the power ports so that I can see what may be the problem w/ the direct short or replace one of the power ports. Thank you for your time, this may not be worth your time but again thanks, stevendb11