Don't let the smoke get in your eyes because it burns ...

[LAZ 1]

Up at 5:30 am for a road trip. DARK!! Driving along on the hiway for about 20 minutes in my 98 2wd camper van.
Engine is warmed up nicely, heater switch set to HOT, air blowing out of the dash hot enough to be uncomfortable on the hands, so I set fan switch down from hi to # 2.

Noticed a burning plastic smell, so shut off fan.
Restarted fan, same smell, turned on the interior lights, and
SMOKE was coming out of my dash by the fan switch.
WHOO HOO!!
and of course I had left the fire extinguisher in the other vehicle.

Pulled over and played with the fan controls.
Switch to # 1 setting, no problem, # 3 setting no problem, HIGH setting, no problem.
But set the switch to # 2 and it gets smoky and stinky.

Since I had a meeting to go to that morning, I left the situation as is ...
with a promise to buy another fire extinguisher and fix it properly ASAP.

Advice from the experts?

possibly resister pack?
possibly switch itself?

[doyoulikeithere]

being that it only happens on the #2 setting, I would try taking the switch out and looking to replace it if its burnt.