I need a electronic genius to chime in and maybe shed some light on this. Ford keypads are a dime a dozen online from what I found...and they are obviously good quality.
Electronic Genius here.
There are four interacting parts in a modern car with a keypad:
1. your car's door locks (usually operated via a communication protocol called CANbus)
2. your car's favtory anti-theft computer (almost all cars have them these days)
3. The keypad of number digits you push (aka the dime a dozen ford keypad)
4. The computer that talks to all of the above, and which you set your keypad passcode into... it watches the button presses, and tells the anti-theft to shutdown and doors to unlock.
Old cars without keyfobs don't have an anti-theft device.. so you can use a very simple version of 3/4 that let you set a code right on the keypad, and which just have two wires someone hooks up to the door unlock to "push" the unlock button.... many of these cars don't even use CANbus for their door unlocks.. just direct wiring for everything.
Modern Ford keypads are "cheap" to install aftermarket because you are just installing #3.... #4 is built into the car computer that runs the main display has the software to run the keypad and to let you set the passcode into the car settings user interface.
A modern RAM truck doesn't have #4 built into the truck software, so you have to add #3 and #4 to get keypad unlock functionality that doesn't set off your factory anti-theft security. Unfortunately, there is no "standard" way to tell anti-theft to turn off, it's manufacturer specific. There might be a way to do this in the RAM factory anti-theft, or might not. If there is no way to turn it off without the keyfob, then it would need to be removed or disabled. However, in some cars this anti-theft is one system that handles both keyfob entry and ignition for the engine, so that creates another mess.
Add to this, the fact that if you want to lock the car but keep the keyfob in the car things become more complicated. Normally, if you have a keyfob sitting on the front seat, it is detected "nearby" and the doors will unlock. Ford's keyfob computer has special programming, so if you leave a keyfob in the car, but you use the keypad to lock the doors... it *disables* the keyfob unlocking, so the doors remain locked until you use the keypad to lock them again.
I have wondered if a simpler way to approach this problem is more like the way garage door keypads work. They effectively act like an additional secure opener, and when you enter the code, they send a secure rolling code signal just like a normal garage door opener does. For the car, this would mean adding #3/#4 and custom wiring them directly to a keyfob chip from the car company, so the whole thing would "look" just like another keyfob. However, the companies don't sell these keyfob chips directly, so I'd probably rip open an existing keyfob and wire directly to the buttons in it.... which could work for me, but would be a big mess to try to give to anyone else.