it was about 15 degrees outside, and i was eating lunch in my van while it was idling, when all of the suddden smoke started pouring out from under the van, from the auxilary heater area under the drivers side floorpan.
i shut the van off and waited a while. started it back up and no more smoke and the auxilary heater running fine. what gives?
and what fuse can i pull to shut the auxilary heater off if it keeps reocurring?

If the aux heater (or any Webasto or Espar product) has ingested a bit of moist or otherwise contaminant laden air they will smoke at start up and take more than a few minutes to clear. Sometimes the moisture can just be as simple as a bit of condensation in the intake pipe.

They usually clear up by themselves because once the unit see's flame in the burner, they will operate as requested and burn out any gunk.

IF.....it does it EVERY time it starts and then clears up...the glow pin in the heater is likely bad or very weak.

IF....it does it continuously EVERY time it runs...it is starving for air either by an obstructed intake or a poor performing combustion fan.

Either way...it would be highly unlikely there would be any harm other than the smoke show....it really is a small fire going on inside the unit, unlikely to barbeque the van.

the van had been running for a long time when this occurred, so the heater was definetly warmed up and had been running for a while.
it seems something caused the flame to go out, and the fuel kept spraying inside the heater, hence the heavy smoke.
there is no smoke on start-up. i guess i'll just keep an eye on it and see if it happens again.