I had two problems with opening my tail gate: First, like the OP's problem, my tailgate hits the power tongue jack motor and second when the tail gate is opened all the way it will hit the hitch ball lock on the trailer tongue. Here is what solved those for me: I found that if I run the tongue jack down and lift the trailer tongue just a little the tailgate now misses the jack motor. I don't open my tailgate often when hitched up so this is no problem. On the second problem, there are two posts on the truck that serve the following purposes; the lower post, on each side where the tailgate closes, is where the cables connect that stop the tailgate from opening any further than level with the truck bed. The top post on each side is where the tailgate latches latch when closed. If you open the tailgate and lift it a little to get slack in the cables, you can then detach the cables from the lower post and attach them to the upper post. That does not interfere with the latching of the tailgate. Now when you open the tailgate the cables stop it a few degrees before it is level with the truck bed and before it hits the trailer tongue ball latch on my rig. I leave the cables in this position all the time. Works for me! My truck is a Ram but I think this will work on most if not all pickups.
