etrailer has the t harness ones. i had one, after 3 months the module fried itself. couldve caught my jeep on fire, but i smelled smoke and disconnected the battery. when i contacted tow ready (company that makes the harness) they basically told me i probably installed it wrong and they couldnt help me. i didnt even get to use the damn thing! theres 50 bucks down the toilet. i ended up going to the junkyard and found factory wiring from a ZJ. i went to the junkyard late in the day right before closing, and when i got up to the front, the guy told me the registers were already shut down, so he let me take it for nothing! super easy to install and it gave me a 7 way, rather than a flat 4 with the tow ready harness. the factory harness runs to the passenger side and goes in thru a hole in the floor inside the passenger side interior panel in the trunk area. it plugs in to the relay set (grab that from the junkyard too if you dont already have it) and the relay set plugs into the main wiring harness. the plug will be there regardless of if your jeep came with trailer tow or not.
Reliability is relative