Here are things I have noted about the problem, plus some extra info that might help here:
1. The smell seems mostly electrical with a hint of coolant (I dont use dexcool, btw).
2. When it began, there were small unidentifiable white flecks (not like ice flakes from a frozen AC coil) and enough smoke to haze the windshield very badly (not water condensation).
3. The problem is only when the engine runs and only from the dashboard area. The problem doesn't change whether it sits running in the driveway or it is moving down the road.
4. I changed the lower intake gasket, all the hoses belts etc., plus the heater core and radiator 4 or 5 years ago. It has run great ever since then.
5. The AC and heater still work just fine, and the problem doesn't change if you turn the climate control and the fan completely off.
Notes: The defroster vent grill has been missing for years, but I don't think anything combustible has fallen down inside. This is a 2001 two door, rear wheel drive model w/ the 4.3l engine.
Has anyone ever heard of a fan motor going out like this? What about the resistor they stuck by the blower motor (under the hood, but still part of the whole blower assembly)?

I have probably omitted a few details, so if anyone has questions, please feel free to ask.
Thanks to any and all who submit their thoughts or questions about this.

 

Update: A blocked evaporator drain is suspected. I will have to remove the passenger side front tire and the wheel well to see under the evaporator housing. When it is all back together I get to do it again on my S10. More fun for me, lol.

 

I have the same thing going on the heat vent had smoke coming out it and odd smell too. The heater vent has been making loud sounds on 3 and 4 for awhile now and keeps losing antifreeze. Was thinking it was the blower motor but saw on line is heater core. Price could be 450 to 600 instead of 140 if it was the blower motor only. I thought the guy could put some heavy duty stop leak in the radiator as well.

 

Did you ever get to the bottom of this? I'm having something similar going on by the sound of it. Some coolant is leaking down around my wheel well too.

 

The coolant is leaking inside the truck onto the carpet or outside the cabin. Which side?

George

 

Outside, passenger side. I replaced the heater core about 5 years (40kmi) ago. This time the coolant is not appearing on the carpet but behind the passenger side wheel well outside the car.

 

There are a couple of possibilities. One is a standard issue hose/clamp leak which should be pretty easy to check. Also, water pump, thermostat housing, radiator, etc.

The other possibility is the lower intake manifold gaskets. These were a bad design and most of us end up replacing them sometime after 100,000 miles. Have yours been done? Do you have any coolant in your oil?


George

 

No I haven’t had that checked but I haven’t noticed coolant in the oil either. My water pump was leaking but was fixed A week ago, before the smoke came out the vents today. And there is def still another leak. Would I be able to tell if coolant was in the oil with just Using the dipstick?

 

Eventually its obvious because your oil starts to look like chocolate milk and the level starts rising on the dipstick.

You also have smoke coming from the vents inside? That's either a blower motor that's burning out, a leaking heater core or smoke coming in from the engine bay. If you put it on defrost, do the windows fog up? What does it smell like? Burnt wires, sweet?


George

 

with defroster on I get a burnt smell but no fog and no sweet smell from what I can tell. Fog might be tough to see bc it’s still warm in SoCal. But I wouldn’t describe the smell as sweet. Also The “smoke” was only visible one time. Now it’s just an odor.