SEIDO

iTrader: (1)

I was replacing my lighter unit, which hasn't worked for some time. It made no difference however, as the replacement didn't work either. I checked the fuse (15A) and saw that it was blown, so I replaced it, and still nothing. However when I put it all back together, my HVAC (which was just on; since I warmed up the car to work on the lighter) just stopped working!
It lights up, but there's no display on the screen. I hit the button and nothing happens. I hit all the buttons and nothing happens. I checked all the fuses under the hood, and they're fine ...
Why would my HVAC unit just go out like that???
Now I'm gonna freeze my a** off, everyday until it's fixed.
What could it be???

t2d2

iTrader: (8)

What happens if you pull the lighter fuse? I'm guessing it was blown in the first place because of a short, and re-enabling that circuit with a new fuse recreated whatever the problem was and is now interfering with the HVAC.

Has your lighter wiring been tapped into for aftermarket stereo or other electronics? That's pretty common and might be a good place to start inspecting.