I purchased a BeCool p/n 75099, which makes at 210 and breaks at 190. I purchased it from Summit, and it arrived on my doorstep shortly thereafter via FedEx (which rapes us in Alaska) for $53 IIRC.
The BeCool switch is significantly longer than the OEM switch.
It is a 3/8" thread, and fits into the OEM T perfectly.
Even though it's longer, there is no worry about it bottoming out.
I soldered and shrink-tubed a ring terminal for the top post, and trimmed two spade terminals to plug into the OEM harness. If you don't care about your OEM harness, feel free to hack away your OEM connector and solder or ghetto-fab directly to your harness in whatever manner you prefer. I personally didn't want to be a DSPO should we ever get rid of this ZJ or should it eventually end up in a junkyard, or should the aftermarket decide to start making OEM-style switches.
The BeCool switch is designed to ground through the surface it's screwed into. That's problematic for us since the hose prevents a ground. Because I didn't want to modify the OEM T, I took a large diameter ring terminal, hogged it out a little with a carbide bit and a die-grinder so that it would fit around the base of the switch, and called it good. This also allowed me to use teflon tape to seal the threads without harming the integrity of the ground connection. Again, feel free to weld a nut to the T for a machine screw or weld a tab or do whatever you want to create the ground connection. I recommend NOT putting a screw directly into the T because you'll just create a new opportunity for a leak.
IF SOMEONE KNOWS A SOURCE FOR THE CORRECT PIGTAIL CONNECTOR TO THE OEM HARNESS, PLEASE POST UP!
Because I wanted to be anal, I plugged my half-spade terminals in and shrink-tubed around the assembly (please note that in this photo, the wires are crossed; the post terminal on the switch SHOULD be connected to the connector on the side with the tan wire with tracer. I incorrectly installed it in this photo. It is critical that the tan wire with tracer is connected to the switch post, and that the black wire is connected to the T or the switch base. The BeCool switch will NOT work in reverse.
Added some wire loom just because.
Taped the whole assembly up.
Using my cheap OBDII scan tool (I should note that we had an ambient temperature of 31 degrees F), the engine went up to 212 when the low-speed fan relay turned on. The temperature went down to 190 degrees, and the low-speed fan cycled off.
BOOM! Problem solved. So long as BeCool keeps making this switch, we have a solution.