2021 Start button not working. RF module failure??

[MrSixStrings12]

So my Ram has left me stranded for the second time. The first time was luckily just a battery replacement but this time has me stumped. I'm leaning toward failing RF module. The truck will not respond to pushing the start button, with finger or both key fobs. The truck WILL start and stop with remote start. I remote started it and when I opened the door to try and attempted more pressing of the Start button, the dash flashed a "key fob not detected" message.

So what I've gathered is, the truck can detect and will respond to messages from my key fob, but can't detect the key is in the cab. Gonna call the dealership when they open and see what they say as I'm assuming this doesn't fall under the powertrain warranty that I have left.

Strange though, as it DID rain the other day but I made it to and from work before this failure to start happened. I periodically check for any signs of water intrusion at my back window and haven't noticed anything. Unless it's hidden behind the seat, as I don't own the star socket to remove them.

 

[MrSixStrings12]

Update: This morning the truck did not respond to the key fob at all. Checked the battery and its completely dead now. Would a failing RF module drain the battery?

 

[FastBlackRam]

Update: This morning the truck did not respond to the key fob at all. Checked the battery and its completely dead now. Would a failing RF module drain the battery?

When my RF module failed due to water intrusion the first time, it also drained my battery. Not knowing it was the RFM that was failed, I replaced the battery but still no key fob recognition at all and when I tried to open the door using the key it set off my alarm which I could only stop by disconnecting the battery. After RFM was replaced, all good. FYI back window was leaking for years unbeknownst to me (I know stupid me). My story is a lot longer but no sense rehashing here. Yes the RFM killed my battery.

 

[RRK]

Just had similar issue with my 2020 Ram a couple days ago. Went out to leave for work after having zero issues, or even a sign of any issues, and when I hit the button it was dead. The key fob wouldn't lock or unlock the doors, so assumed the battery was completely dead. I put the battery charger on it and left for the day, came back that night after it charged all day and the fob locked and unlocked the doors, but still nothing when I hit the start button, wouldn't go to accessory, did absolutely nothing. Hooked jumper cables up to my daughters truck and still nothing, took the battery out and connected an extra battery I had and still nothing. So put the original battery back in and tried the remote start and it started right up. Got inside and hit the push button and still nothing, wouldn't let me shut it off unless I used the remote start again and then it shut off. Got back in and tried the button, still nothing, got out and tried the remote start and it started right up. Crazy I know...

So at this point I'm thinking it can't be the battery, or the starter otherwise it wouldn't have started with the remote start. I started thinking maybe the push button went bad but when looking at Ram forums many tried replacing it and it didn't fix the issue. That's when I found out about the RF Hub Module. I also saw a You Tube video of someone taking one out of a 2019 Ram, cleaning it up, and putting it back in and it fixed the issue.
This afternoon I removed the back seat.....I have a quad cab so for those who don't know, because I didn't, the back of the back seats don't fold down like the crews, only the bottoms fold up so you have to remove the seat. You can actually see the RFM mounted to the back of the cab when I folded the seat up, but not a lot of room to work to try to get it out. You probably could if you messed with it long enough but I thought it was easier to just remove the seat. I took the RFM out of the truck and opened it up and took the circuit board out. No signs of water damage that I could tell, not moisture, no obvious corrosion, nothing looked unusual to me. I took a small soft brush and lightly scrubbed both sides of the board and the inside of the black plastic case. I then blew everything out with the air compressor before putting the board back in the case and closing everything up. I went back to the truck and plugged everything back into it and headed to the front to try starting it again. When I first hit the button it again did nothing but when I hit it a second time it fired up like it's supposed to. I let it run for a few minutes and shut it off, let it sit for about 5 minutes, and then tried it again and it started again. Did that a couple more times and it's started every time so far.

Tomorrow, assuming the dealership has a new RFM in stock, I'll take the truck in (thankfully I won't have to tow it in IF it starts) and I'll buy the new one. I'm told the dealership will have to program the new one to the truck so I'll take both key fobs when I go and hopefully this will take care of it. I saw another You Tube video from about a year ago where someone had the dealership do the replacement and they said it cost them $1,800. I'll report back the cost of the part which I think is around $300 and then whatever they charge to reprogram everything. Hopefully when all said and done the issue gets resolved and for much less than $1,800!!!