I have a 99 Chrysler 300m when I turn the heat r ac smoke comes from the vents and from under the hood.. When I turn the heat/ac off it stops.. It has a smell like burning rubber

SOURCE: Burning smell when ac is turn on

well as for the ford man sorry to here that. I am a holden man myself, but it is most likly that your fan switch is on its way out if you have a test light just pop the switch out and see if you have power to your high setting if not replace your switch. And for mgauthier I would suggest you just reroute your overflow pipe so it overflows onto the ground not onto hot metal parts. But you shouldn't have coolant coming out your overflow all the time. As for burning smell it was probably the switch burning out and failing.

SOURCE: 97 cad sls white smoke near windshield smell like rubber burning

If its in the engine compartment there is an antifreeze leak..If it inside the car like like near to the windshield, you have a bad heater core. Good Luck contact me if you need more help.