Truck is 2003 Laramie 5.9L Diesel- Blower doesn't come on at any speed. The a/c compressor cycles on for a short time so that seem OK? I CANNOT locate a fuse that I can identify as blower motor?? Could someone get me straight with that? That was my first guess as a starter to problem. Some other person with problem similar indicated it was tied it with brake and accel adjustment which is working so maybe it not the fuse? Any other paths I should try to go down??

 

If I recall correctly the + end is fed off of the ignition switch in those years, and - is completed through the selector switch and through the resister block when in a speed less than high.

There were some threads about charred wiring around the ignition switch, and/or the switch it's self. Later model trucks powered the fan off of the TIPM.

Have you checked the motor? They can also fail, and the recirc door has been known to break and fall onto the blower.