Has anyone replaced their o2 sensor?

Ok, Only things I can think of.......Your heater lines run behind your dash, and if you have a ton rubber grommet in your firewall, air may be blowing on them bringing the heat to where it can be more easilly felt. This is very unlikely. Look under your truck and see if there is some heat shielding missing. The prior owner may have taken it off for some reason or another. Also, if it is near the gear indicator, I belive the lights in it are opperational all the time, thus emitting heat. That combined with the fact there isnt much in the way of heat protection in that area could be the issue. How "hot" is it getting? FWIW, the Fog light switch on my Dodge gets very hot in the dash. Dealer said it was normal, and it has been that way for 175,000 miles. Just some info that some things DO radiate a little heat in the cab.