Suburban NT-16SE furnace troubleshooting

Mine will actually perform the complete cycle including lighting and producing heat. However after a short time the fan sound like it slows and the lights dim then it blows the 15 amp fuse.
The lights and the furnace are not on the same circuit as the lights stay on after the fuse blows.
The only thing I can come up with is the the blower motor is pulling excessive amps and is the culprit.
Are there any other thoughts?