There is absolutely NOTHING wrong with tying into the factory wiring for using jeeps tail lights as toad lights, UNLESS, it's the newer model JKs and JLs. Both have vastly different wiring than the previous models and, the '18 and newer JLs, have LED tail lights. They also have side mounted range finders in the tail lights for blind spot recognition.
Soooooo, tying into those models tail lights by the old fashion way with diodes IS OUT! I've done the "old fashion" way of tying into the tail lights on oh, maybe 30 or 40 Jeeps and not one of them has ever gone up in flames because I did it that way. This is one of those things that, if your skill level is up to par, you'll have ZERO issues doing it that way. If you're not sure what you're doing, then either add sockets and bulbs or, leave it to a pro.
The JKs, from '07 (first year for the JK) through oh, about maybe '12, is fine wiring them with simple diodes. From about the '14s up, you're better off using the Hopkins model of wiring harness. Waaaaaaaaaaaaaay cheaper than the Mopar version and WAAAAAAAAAAAAAAAY simpler to install.
If you're blowing diodes in ANY FORM of regularity, then somethings not wired right. I've had simple Radio Shack diodes in one of our toads, an '11 GMC Sierra 1500 4x4 Extended Cab now ever since 2011 and guess what, THEY'RE THE SAME DIODES I installed way back then and, the truck's got probably around 20,000 miles of towing on its clock. Hasn't burned up yet. And those diodes cost me a whole whopping $3.50 for a four-pack at Radio Shack.
Now, on our other toad, the '15 JKUR, I'm using the Hopkins unit and like stated, it was cheap, about $45 if I recall and it's been in there for 2+ years. But, I'm thinking of changing my thought pattern here. We haul two bicycles on the back of the Jeep and, for the most part, those bikes pretty much cover up the Jeeps tail lights. NOT GOOD! So, I'm thinking of going to plan B.
And that is to mount some really nice, THIN, vertical LED stop/turn/tail lights right to the vertical pillars of the rear of the hard top. If done correctly and with a bit of finesse, It's gonna look and function flawless. That will get the lighting up higher for way better viewing from folks following us when we're towing and carrying the bikes.
Then there would be no need for the Hopkins unit after that.
Scott