Key Fob Unlock not Working - Lock Still Works

This is on my Dad’s 2019 TSS Tundra. Bought used recently and he thinks the entire fob worked at the beginning, but after about two weeks it stopped. The unlock still works.

The dealership says it will be $350 for a new fob. That’s what I’m seeing online too.

I’m home now for the holidays (Birmingham, AL) and I was hoping I could sort it out. Took it apart and don’t see anything indicative of a physical failure in the fob. Any creative ideas on what’s going?

I really appreciate this community! Happy thanksgiving.

 

Without a schematic it would be difficult to say. The only other method is to measure voltages/signals with a fully functional fob.

 

So lock works...... what isn't working?

 

The unlock button isn’t working.

 

Okay, thought you meant the locking system works, not just the lock button. So now that that's clarified, while you have the circuit board out of the fob housing, try spraying the unlock button with some CRC Electronic Cleaner https://www.walmart.com/ip/CRC-0510...ZBSrggvp3RPBBUaLINS&athancid=null&athena=true and operate the switch a number of times. All this without the battery, just to try and clean the switch. The switch contacts are enclosed in a tiny housing, but some cleaner should work its way in as you cycle it. The spray cleaner dries fast and won't hurt the circuit board.

If that doesn't work, then you're probably looking at replacement.