Bryant 350MAV, LPG, approx. 11 yrs old. This winter my Bryant started making noise on start up until blower motor switched on. It has gotten progressively worse and appears to be the Pressure Switch vibrating. When I hold the switch the noise stops. On this model the pressure switch is located beside the inducer motor. The inducer motor is not making noise;however, its the only moving part that I believe could cause the vibration of the switch. I'm looking for suggestions on what else to look at and if you have run into this - what part(s) needs replaced.