So the other day my blower fan just stopped while driving. Later that night when I got back into my truck and after I drove off it started working again on second from high speed, and then suddenly on high speed again. This morning it worked, but I wanted to look into the problem. We took out the resistor pack, and it showed obvious signs of burn spots, so we replaced it. No fan still, so I checked for voltage at the fan motor connector, and it is getting there, so we put in a brand new blower motor as well, and I still get nothing. I'm wondering if I got a bad motor, but before I return that and try again I wonder if there's anything else I need to check. All of the controls on the climate control panel are working, so I don't think the issue is in there.

 

Well, after a bit of frustration I was actually able to figure it out, the resistor pack we got was defective, something told me to try plugging the old crusty one in and see what that would do, and the new fan worked, still minus the two lowest speeds, and as I found out later it wasn't really getting true high speed either. So I tool the defective one back for a replacement. The defective one was identical to the original one (minus the corrosion and burnt spots), all black with what looked like a large black plate for the resistor pack, the new one has a white base with resistor wire wound around a white ceramic bracket, more like what a typical resistor pack looks like. With the good one installed all the speeds now work and the fan blows much harder on high speed, its never had that much power. So apparently it was the blower motor that finally died on me, and the partially working resistor pack still worked, however was still obviously in need of replacement.