Hi, first off, this forum is fantastic for info and all of you are great. Second, this is going to be long because this issue just won't go away and I'm at my wits end. Third, I hope this is the correct board to post this, I didn't see a generic help section.

Background: Stock JK, bought it with about 90k on it and had no issues for first three years and then a cascade of issues (mostly involving overheating and cooling system).

Issue: About two years ago I noticed the stock rad was leaking, I replaced that and both hoses myself and didn't have any issues for about another 6-7 months. Then the temp gauge started spiking up to the 3/4 mark on the highway, it never went red and I've still never received a dash light for overheating, but I'm paranoid and I've never let it go for too long without stopping and letting it cool off. That's essentially the issue, overheating and the rad fan kicks into jet engine speed, but it never actually red lines and overheats.

On to what I've, or a mechanic has, replaced/performed, in, more or less, order:

• coolant flush/burp x A lot (heater core needs to be replaced, but isn't completely broken). For disclosure, I've been using the Zerex G05 50/50 prediluted coolant.
• thermostat x2
• coolant temp sensor x2
• water pump x1
• fan x1
• both fan relays x1
• tipm x1

Where I'm at now: The local dealership apparently has a wait list for new service customers so I haven't taken it there. I'm using a mechanic now that seems to want to figure out the issue out of professional curiosity, which I like. The fan works (ish); driving around town I don't get any issues, but anything faster than 40 for more than 15 minutes and the fan goes into high mode and the gauge starts spiking. The mechanic said the TIPM might be bad, so I just went ahead and bought a new one from MOPAR. Got that installed and the fan seemed to work for about a week and then back to the same issue - kind of overheating and throwing the P0480 code. It's also now throwing a P0522/P0520 code for oil pressure sensor, but I'm trying to ignore that for now as it seems unrelated. Current mechanic said the fan stopped working altogether, so I took it back to a different mechanic to get it replaced under warranty - I've taken it all over town, and the warranty was through the other mechanic - and they replaced it. It's a brand called Matrix. Now I'm back to square one with the P0480 code and the fan seemingly working fine, but unable to keep the temp cool enough to not have to jump to jet engine speed after a while of normal highway driving. Current mechanic says he's getting correct power to the fan. I've been thinking maybe a weird ground, but I'll be the first to admit I don't understand how to diagnose electrical issues. And a weird ground seems like a needle in a haystack situation.

Shortly after replacing the rad (about two years ago), I replaced the spark plugs because the manual said it was about the right mileage to do that, and I replaced the upper intake manifold gaskets while I was at it. I only mention that because I thought maybe there could be an internal coolant leak, but I haven't noticed the soupy coolant symptom and the 0480 code seems, to me, would rule that out.

I've poured over so many posts here and wrangler forum, and the real jenius write up, and I'm just at a loss now. I'm about ready to find a jeep head who's willing to buy it and diagnose it in their free time. This is a basically a hail Mary that one of you fine folks has had a similar issue. Thanks for reading if you made it this far.