Hello! Welcome to the forum! I'm unsure of what you mean by "Tried a different key fob", did you replace the key fob itself?

If not, I'm thinking this might be something to do with the key fob rather than the van itself, especially if the rubber buttons on your key fob were never changed. There are contacts that are glued to these rubber buttons that commonly come loose inside of the fob and can cause many issues, including that.

I would recommend taking apart your fob(s), it's really easy to do and there's plenty of videos online. If this is the issue, at least one of your fobs lost the contact for the panic button and it's setting off the panic button without you pressing it. If this is the issue, you can either do a temporary fix with some glue (it won't stay, I've never had luck with these key fobs with that method), or you can go onto amazon and buy the replacement rubber buttons themselves for really cheap.

While this may not be it, it's a good starting point. Good luck!

EDIT: Here's a good video that covers this as well.

 

Spot on advice! I recenlty acquired the TC and both fobs are "new" (guessing new shells, original internals). I popped open the main key, removed the circuit board and battery, and reseated the rubber buttons. When I reconnected the car's battery it was still in panic mode but I pressed the panic button on the fob and it stopped! Curiously, the second key only starts the vehicle - none of the other key functions work. The person I got the van from told me this ahead of time about the second key.

 

I'm glad at least one of them works now! That's definitely weird for "new" Fobiks for sure, they're probably rebuilt or cheaper aftermarket Fobiks.

Curiously, the second key only starts the vehicle - none of the other key functions work.

That's definitely weird, does it make a clicking sound when you press down on the buttons?

There are a few possibilities for this, from most likely to least likely.
1. Is the van giving a battery low message on the EVIC? The battery in the Fobik could be worn down enough to not allow it to communicate with the van from a distance, but still start it.
2. The Fobik was improperly programmed, only allowing it to start the van and nothing else.
3. Somehow all of the contacts on the circuit board could be dirty, that could've definitely happened if these Fobiks were rebuilt with new shells/buttons, usually just wiping them with a dry cloth, alcohol, or contact/electronic cleaner (in severe cases) can get any stubborn dirt off.
4. The circuit board in the Fobik itself could be damaged/defective.

If these were truly new (OEM or Aftermarket) Fobiks, I'm going to guess that one of them could've been improperly programmed? If this is the case, you could spend money on AlfaOBD or AppCar-DiagFCA and a compatible OBD-II Scanner (Like Veepeak), or you can have a locksmith and/or dealer reprogram it for you. If you would happen to do that yourself, I can give more information on that later.

If these are rebuilt Fobiks, with new shells and rubber buttons, I'd guess that they either missed out on replacing the battery, they could've improperly seated the rubber buttons (you might notice this if the buttons are hard to press/don't make a noise), or the contacts could be dirty. I'd probably recommend taking apart the non-working key fob and inspect the internals for anything out of the ordinary.

 

When I got my van we had 2 keys for it. One in a Dodge case, the other in a Chrysler case. I kept the Dodge fob and gave my then wife the Chrysler one. She used it more than me at first, but eventually she listened to reason (😮) and swapped to using the other car to save on gas since she worked 10x the distance from home. Some time after I started driving it, her fob stopped working. Changed batteries, switched button pads, nothing. Took the battery out and threw it in a drawer. I'd occasionally take it out and try it, waiting weeks then months between tries. After several years, and at least 6 months since last try, it started working again. No clue if it'd still work as we divorced 2 months later.

My thought is the rolling code got desynced and it had to wait for the code list to roll over and get back into the same sequence the other fob was at. This fob would not unlock the van when acting up, but would start the engine.. after setting off the door alarm because you had to use the key, but often not on the first attempt.

I would suggest throwing that fob away and getting another to program in. Save the cut key out the back to put in your new fob. You can program them yourself with AlfaOBD. Don't know how Mango's talking about reprogramming a key... these are one time programmable without board modification.

 

I would suggest throwing that fob away and getting another to program in. Save the cut key out the back to put in your new fob. You can program them yourself with AlfaOBD. Don't know how Mango's talking about reprogramming a key... these are one time programmable without board modification.

Yeah I thought I read somewhere awhile back that they could be reprogrammed (To the same vehicle, as they're married to the WIN module after the initial programming and cannot be programmed to other vehicles), plus I've also reprogrammed other fobs for other brands, but never a Dodge/Chrysler product. But I'm guessing that might not be correct for these then? My apologies.

AlfaOBD/AppCar does still works to program a new Fob without having a locksmith or the dealer program it, usually for significantly less too. It's $56.70 for AlfaOBD, which is a one-time purchase, and you can use it on multiple dodge/jeep/chrysler/fiat products, or currently $29.95 (On sale) for AppCar-DiagFCA, but each license is for a single VIN.) Both are very similar aside from that. I use AlfaOBD personally, and there's both a Windows(PC) and an Android(Mobile) version. You'd also have to purchase a compatible OBD-II scanner that works with whichever program you want to use.

I could've swore that at least AppCar-DiagFCA allows you to reprogram a key fob that was used on the same vehicle, for that vehicle. I'm aware that you can't pick up a set of these Fobiks that were already married to another vehicle and try to reprogram them, that requires erasing the memory off the Fobik which is more of an advanced locksmith's expertise, and it's pointless when there's new Fobiks on the market for pretty cheap.