I have a 94 Pontiac Bonneville SSE. About a month or go is when it started. When ever I turn on the heat I start hearing a very loud noise that changes pitch. At first it would happen every once in a while start for a few sec then stop. After a while it would be even longer and now I am to the point that it is very loud when i turn the heat on and I can feel vibrations in the gas pedal. What could possibly be the problem? It gets pretty cold here in DC and no heat is not fun.

Thx

I strongly suspect your blower motor. It'* the bump in the firewall (behind the engine under the hood). Just behind your rear exhaust manifold.