My 02 2500 does not read the temp on the mirror. It is completely blank. The little green light is on at bottom of the mirror. Any common things to look for? I have seen bad temp sensors before but they still read something.
The mirrors do fail, especially now that they are pushing 20 years old. You can grab replacements on eBay or at the junkyard, and should be back in business.
check for 12 volts at the connector on the back of the mirror. I think it's the yellow wire. if no power then SIR fuse. if power then mirror is likely bad
There are many videos on you tube about fixing this. There are 6 or 7 resistors where their solder joints fail. I took my apart and re soldered them and the mirror works great. Took about 1/2 hr to repair this. Here i the video I watched.