I had this for awhile a couple years back and I never did figure out what was burning; that is, until the circuit finally quit. Which circuit? The ventilator fan.
So I took the fan speed control off from beneath the dash, it had arced and zapped and flat-out quit. It's just a bunch of power resistors that, depending on which speed selection your fan speed knob is set at, limits the voltage going to the fan motor. I was mildly unimpressed by the low-tech solution, and very unimpressed when I found I couldn't get a new replacement. So I took the old one and soldered it back together, it has worked ever since (but I smelt it cooking once more since then -- I quickly turned off the fan for awhile, and it hasn't acted up since). Take a look underneath the passenger side of the dash, if I remember correctly that's where you'll find it. If you see any discoloration indicating burning, there's your culprit.
Just take it off, it seems to me it came off easily enough (power plug and one or two bolts) and have a close look in the light of day.