Please help...furnace acting up !

[Moosewilliams12]

Let me first state that this has to be the most helpful and informative website to be a member of.
Sir i have researched the other posts about my problem but failed to locate a answer.we have a 1980 mobile home with a 2 year old Coleman furnace- it only blows cool air . Not even warm! Looking into the glass on the unit it's ignited but the flames are more yellow than blue. Can you PLEASE shed some light on this problem? Thank you sir.