My '94 250 is throwing out some chemical smelling fumes when the AC is running. Seems to start smelling about 15 mins after its turned on. Still throws out cold air. Can't put my figure on the smell but its definitely not gas/exhaust or antifreeze. Anyone else out there experienced anything like this?

 

Does it smell electrical? Possibly the blower resister has debris on it.

 

Are you sure it's not anti-freeze? When the heater core begins to fail, the anti-freeze will vaporize and exit the vents as a slightly sweet smelling mist. About 15 minutes could be the amount of time it's taking the t-stat to open and begin circulating warm/hot coolant into the heater core. Just a thought.

 

if your on regular a/c or vent its pulls air from the cowl vents and anything coming off the engine will come in the truck. its not as much on max a/c but you will still get some.