I don't know, you have to trace wire's and do the diagnostics like the FSM says. As far as the fuse goes, I'd say it's the IOD fuse. But I think you need to check output from the switch and trace to the mirror. Maybe a wire is broke inside the rubber boot or the heat filaments are bad.

 

On mine, the indicator light does not light up. I'm gonna try to find a spare climate control switch...

 

Then your problem is before the switch.