Had a weird one happen a few years back. On a trip from Ontario, Canada to Arizona we took the I-80 to I-76 to I-70 route. After we passed through Denver, we saw and decided to check out the Buffalo Bill grave site just up I-70 as you head into the mountains west of there. When we parked our older Roadtrek, on a Chevy Express 3500 van, and tried to use the factory fobs to lock/unlock the van's doors, they wouldn't work. No lock tumbler clicks, nothing. We had to use the keys to physically lock/unlock the doors while we were stopped. We figured it must have been the iron or other metal ores in the mountains somehow blocking/suppressing or otherwise interfering with the transmit/receive signals from the fobs. Once we got back on the road again, they were fine. Remote control resumed.