Key fob not working after replacing dead battery

My wife keeps my backup fob and tried it yesterday, but the fob battery was dead. I tested the battery with voltmeter to confirm. This fob hasn't been used in years so the battery in it has probably been dead for months.

I replaced with a fresh CR2032 battery, but the fob still doesn't work. Tried a 2nd fresh battery and still nothing. I tested voltage on both the new batteries they are both good (3+ volts on each).

The backup fob does, however, still start the truck when it's touching the start button. Also, the main fob still works normally.

Google nor TW search had nothing on this. Any ideas?

 

Sometimes those coin batteries don’t make a good contact. Double check how your battery is sitting in there. I had one where it looked great but had to bend the tabs on the fob a little to get good contact. Of course also possible fob is just dead

 

Update for anyone else this helps. I had checked the contacts and they were good.

However, after just leaving the new battery in for a few days the fob randomly started working. I did nothing else other than letting it sit with the new battery for 3 days. Now it works like a charm. Maybe having been dead for a long time required it to have a continuous charge over time? Who knows but it works now.

 

Weird. Shouldn’t need a “charge”. But glad it works!

 

Maybe this? From the manual, page 124.

Battery-saving function
The battery-saving function will be activated in order to prevent the electronic key battery and the battery from being discharged while the vehicle is not in operation for a long time.

• In the following situations, the smart key system may take some time to unlock the doors.
  • The electronic key has been left in an area of approximately 6 ft. (2 m) of the outside of the vehicle for 10 minutes or longer.
  • The smart key system has not been used for 5 days or longer.
• If the smart key system has not been used for 14 days or longer, the doors cannot be unlocked at any door except the driver’s door. In this case, take hold of the driver’s door handle, or use the wireless remote control or the mechanical key, to unlock the doors.

The system will resume operation when

• The vehicle is locked using the door handle lock switch when carrying the electronic key on your person.
• The vehicle is locked/unlocked using the wireless remote control. (→P. 109)
• The vehicle is locked/unlocked using the mechanical key. (→P. 557)