Interesting Fob issue.

[Lee955i]

2021 Bighorn. About 3 weeks ago, spent the weekend at a friends house. Parked the truck in the driveway, came out to grab something and the truck wouldn't unlock/lock and I had to use the key to get in. Weird. Get in, no "fob not detected" messages, truck starts right up nothing out of the ordinary and even with the truck on and running, lock/unlock on the fob doesn't work. Drive home, park, and suddenly everything is OK, no issues, locks work, fob works with good range. Fast forward to this weekend. Visit same friend, park in same spot, and suddenly lock/unlock not working again exactly as before. (BTW, this doesn't happen with my Challenger, or with my previous '18SLT ). and once I drive home everything is normal again. All I can think of is some strange RF interference coming from something at these new fobs frequency at this one particular suburban location. Anyone experienced anything similar?

 

[mtnrider]

I've seen several reports of this on the 4.5 gen trucks. Possibly some sort of interference or firmware glitch of the system. It uses 2 separate frequencies, one for the buttons (far away) and another for the near field stuff (starting, door handle open etc). Sounds like you had something going on with the far field but it still saw the near field to start.

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[Timsdually]

My fob was doing similar. I would get in the truck and it would say fob not detected. Even when I took it out of my pocket and held it right against the dash, still fob not detected. Then it was detected and worked. I went to the dealer and got a new battery put in it and haven't had the problem since (about 2 months ago).
Cheap or old battery?? Truck was purchased new Jan 3 with build date 11/20.

 

[GTyankee]

LED lights will conflict with the FOB operation

It also happens with garage door openers & Homelink, if LED bulbs are near the opener
Sometimes bird baths will operating on a frequency close to our FOBS

My 2009 Ram FOB often would not work near the front door of a 7/11
I had a problem also when i went to a machine shop that had a CNC Machine operating

 

[CheechDogg.0n37s]

LED lights will conflict with the FOB operation

It also happens with garage door openers & Homelink, if LED bulbs are near the opener
Sometimes bird baths will operating on a frequency close to our FOBS

My 2009 Ram FOB often would not work near the front door of a 7/11
I had a problem also when i went to a machine shop that had a CNC Machine operating

I was about to make the same comment but saw you did it lol

LEDs are a headache with FOBs and garage door openers, hell even with your radio and phones inside a truck .... a lot of LED companies use cheap leds instead of the ones that don't cause interference so be careful what you put in your vehicles or even around your house ..

On top of all that some street lights and like @GTyankee said, signs at stores can do the same ....

On my street they changed the street lights to some new LEDs that bright up the block, but ever since then our garage door gives us trouble when trying to open or close it ...

 

[Ramdogger]

I was about to make the same comment but saw you did it lol

LEDs are a headache with FOBs and garage door openers, hell even with your radio and phones inside a truck .... a lot of LED companies use cheap leds instead of the ones that don't cause interference so be careful what you put in your vehicles or even around your house ..

On top of all that some street lights and like @GTyankee said, signs at stores can do the same ....

On my street they changed the street lights to some new LEDs that bright up the block, but ever since then our garage door gives us trouble when trying to open or close it ...

I have the same issue and my truck is 1 week old. In the middle of the country with no LEDs, both FOB stopped working at the same time. Something is going on here seriously. And its not the LED lights..

 

[brian42]

Also make sure your cell phone isn't near your fob. Sometimes that can interfere with the transmission too.

 

[Lee955i]

So, I thought I would update this. Took a ride over last weekend and now, suddenly, the fob for my Challenger didn't work, either. After I mentioned it to my friend, I was informed that her mom had the same problem with the remotes for her Caddy SRX. However, no problems with her new Audi Q3. It has to be interference from something in that location, so, i'm not worried it's a vehicle issue.

 

[T2Lee82]

My fob never responds unless I am super close to my 2021 1500.

 

[Timsdually]

I will update my earlier comment.
FOB is giving issues again. Took about 5mins of multiple tries with FOB next to button to get it to start. Occasional door not unlocking and also tailgate not automatically opening.

 

[GTyankee]

One thing that i have wondered about is the Range of a FOB
I seem to recall a youtube video
The guy mentioned that he inserted the battery a certain way, i don't mean face up or face down.
I believe that he meant that he rotated the battery to a certain position & that it extended the range.
I don't see how that is possible, but it keeps coming to mind

There must be some kind of antenna in the FOB, because some ppl claim to have a longer range than others

 

[mtnrider]

One thing that i have wondered about is the Range of a FOB
I seem to recall a youtube video
The guy mentioned that he inserted the battery a certain way, i don't mean face up or face down.
I believe that he meant that he rotated the battery to a certain position & that it extended the range.
I don't see how that is possible, but it keeps coming to mind

There must be some kind of antenna in the FOB, because some ppl claim to have a longer range than others

The battery thing isn't possible (I work in the RF/Comms field) Rotating it will make no difference.

Yes these FOB's have antennas, usually its just a trace on the circuit card similar to the one below. This isn't the exact FOB we are talking about but it kind of gives you an idea of what it might look like.

 

[joeygster]

I've never had this problem with my 4th Gen but am having it constantly with my wife's Honda Civic. In the early days of the issue I just kept thinking it was a worn out fob battery until it happened too many times. I still have not figured out the issue and the car is now out of warranty.

 

[GTyankee]

Thank you MtnRider

So that antenna in the Fobs Circuit Board is a transmitting device & the receiver would be in the WIN Module or the Wireless Hub if the transmitter is an RKE, ( remote keyless entry )

 

[Iceman6409]

So I am having a similar issue. Dodge Ram 1500 5.7L v8 Hemi. This afternoon I did some interior detailing. Cleaning and polishing dashboard and door areas with Meguiars. Used brushes everywhere and cleaned up with micrfober towels. I went to lock the doors and nothing happened. Tried opening locks and nothing happened. They worked if I pushed the buttons on the door. After a minutes I got it to unlock only. I put the FOB down for about an hour. Tried again. Unlocks but does not lock. I changed the battery to a fresh battery. Same thing. Will not lock but will unlock. Any thoughts?

 

[Timsdually]

I started having issues with my fob. Took to the dealer and the said they had to re-flash it. Now it seems to work ok.

 

[stormcom]

I actually had a 2016 Limited bought back because the fobs would not work. I hop they improved things by now but maybe the have not.
Factory rep said stand 5 feet away and try. Did not work while he was there.

I found 2 things that helped

Touch fob to your chin. Sounds funny but they said it increases the antenna.

If it won't start, put fob in front cup holder and try. Also put fob next to push button.

This and a dollar will get you a senior citizens cup of coffee at Mc Donalds.

 

[brian42]

Touching your chin turns your jaw into an antenna to increase transmission range. I did that a bajillion times with my last truck (F-250) so that I could unlock the doors more than 5 ft away.

Touching the front of the fob (rubber end) to the push button (start) removes the need for any signal transmission through the air. The button will read the chip in the fob so the truck will start if you push the start button with the fob. It's the failsafe in case your fob battery dies (or there's too much interference for the truck to "sense" the fob.