Hello,
I currently have a bad ABS module and the dealership says they won't flash one and that I have to wait until March to get one specifically from Mopar.
There are reasons why they're often called stealerships. They're simply trying to force you to pay them to do something you can probably do (mostly) yourself.
Do I have to get a Mopar part because I see they have the same parts online, but they just are aftermarket or unbranded.
There are some people who will tell you that you must always use OEM parts. That's baloney. Jeep didn't make most of those parts anyway. They buy them, slap their label on them, and raise the price. Yes, you need to do some research and make sure the product you buy is from a reputable manufacturer, but quality aftermarket parts are quality parts.
I can't be carless until March. Is it possible to get a part online and have dealership reprogram it? Or should I just suck it up and wait until March. I really have no idea what to do. Do dealerships not flash them anymore? or is it just this one dealership?
You needn't be carless. Your Jeep will drive just fine without the ABS module being flashed. The ABS will not work. So be extra careful to avoid situations in which ABS might be a factor. You will have an ABS warning light, of course, but normal braking does not use the ABS system in any way.
The most widely endorsed scan tool by users here is JScan. You download the app and buy a VIN license(s). A single VIN license costs about $21. You need one of the OBDII dongles supported by JScan. I think most of us here use this one:
https://www.amazon.com/gp/product/B06XGB4873/?tag=jkforum-20
The Dongle is about $31. So about $52 for the tools, which you will absolutely use for many other things besides your ABS module.
The video linked above shows how to use JScan to flash your new module. I've never done it myself, so I cannot vouch for their information.