Originally Posted by nota4re

To make the tailgate swing open and close very smoothly, Jeep uses teflon liners in the hinges which also happen to make a good insulator. However, when the tailgate is closed, the latch mechanism itself will provide a ground. This ground may be good for a month , a year, or two years.... or not, subject to the amount of dirt, grime, and grease that may detract from a good contact. Therefore, it would be a good idea to run a strap to the tailgate (the Teraflex mounting bolt would be a good spot) and a known-good ground in the bed of the Jeep. Also, if the powdercoat is real good where the bolts in the Teraflex are, you may want to use star washers there too (or scuff up the powdercoat) to make sure you have a good ground between the bracket and the tailgate.

In summary, the set-up will work without the strap (most likely) but you will be better off in the long run with a ground strap.