E350 heater fan in the front not blowing

I have a E350 and the heat blows hard in the rear but the front vents won't blow any air hot or cold, which make it hard to see out the windows. I think a wire mite be loose or a fuse could be blown, I'm not exactly sure...
Can anyone give me a suggestion and/or a solution...
Thanks!

I have a E350 and the heat blows hard in the rear but the front vents won't blow any air hot or cold, which make it hard to see out the windows. I think a wire mite be loose or a fuse could be blown, I'm not exactly sure...
Can anyone give me a suggestion and/or a solution...
Thanks!

yeah, i read somewhere that if your front blower moter isnt working, its possibly your heater relay, which is located near your battery. im having the same issue with my heater right now. so im going to check it out in the morning

Had the same problem on my E250 with 173k. Turned out to be gunk built up in the dash switch from the dielectric grease it's assembled with. Cleaned the gunk off the contacts in the switch and it gets continuity across them again. It is usually the resistor though.