burning smell from dash vents when A/C is on

[baksa]

Yesterday I felt burning rubber, plastic or something like that coming out of my dash vents, my A/C was on. I turned it off and smell stopped. Then I turned the vent on without A/C - it was blowing air without burning smell.
After few km, I turned on the A/C when car was on the move and there was no smell, but when I stopped at traffic light, there it was again - burning smell.
I turned A/C off again and spent rest of the day without it. Today there is no smell with A/C on, standing or driving.
Anyone experienced something like this, and what do you think where is it coming from? I'm afraid of a fire under hood - when you notice it, it's already too late.

[Tiger]

Change your microfilter.

[genphreak]

Are you sure it is not coolant you are smelling? If so you need a new heater box and/or o-rings and/or replacement pipes too.

[baksa]

No, it is not coolant, it's more like a burned rubber or plastic smell.
I also turned A/C on today, and there was no smell.Car is not loosing coolant.

[Bleeding_Knuckles]

Maybe it is oil dripping on the exhaus this happened to me before

[632 Regal]

can you smell it from under the hood at all?

[calmloki]

Toasted a wire? AC specific fan motor getting ready to go TU? Bad/gummy electrical connection in the AC switch area giving you a burning wiring smell as it tries to make connection? My bet would be on the latter - have you been spraying any contact cleaner around?....