2007 9400i fan high blows breaker

Works fine on 1 - 3. On setting 4, it runs about ten seconds, and trips the breaker.

I've read the other threads. Here's what I've done: Replaced the resistor, swapped breakers, swapped hi-speed relay. When I replaced the resistor, there is an L-shaped shroud under it. It was facing the blower motor, and that's how I reinstalled it. Is it to keep airflow off the bottom of the resistor, or is it installed the wrong direction, and it's actually a heat shield for the plastic housing? Could that be my problem, or do I need a new blower motor? Thanks.

 

Finally got around to replacing the blower motor. F'n thing still tripping the breaker. As I was swapping breakers around to see if it was just a bad breaker, I realized it had a 10A breaker where it needed 30A. I put in a 30A breaker, and it runs good now. Thing is, the breaker was getting so hot, I could only put my finger on it for about ten seconds. Got my temp gun, and it's reading 134 degrees! How hot is too hot? If I run the bunk on high, it's 30A breaker only gets to about 120 degrees.

Edit: I also metered all the wiring, and I'm getting no continuity to ground on any hot wire. Not at blower motor wiring, circuit breaker, resistor, nothing. I don't *think I've got a short.

 

Yes, and also no sign of arcing at the terminals. Wiring on the truck is actually in pretty great shape considering the rest of it. I swapped a 20A fuse in to see what would happen. Got up to 151 degrees, but never popped. So I put the 30A back in, and I'll call it good. Wiring gets hotter than that near the engine, but I still think something must be wrong. Thinking the only way to fix this begins with doubling the coverage on my insurance policy.....

 

I shot the wiring too. Sitting about 101 degrees. It's heavy gauge wire heading to that fuse. Even the relay for that circuit gets up to about 115 degrees. Maybe the blower just pulls a lot of juice?

 

Well, I was actually in the middle of pulling that section of fuses out of the fuse block, but decided not to. I wanted to inspect the back side of it, but didn't feel like "welding" inside my dash, and I didn't feel like disconnection my negatives either. At that time, I'd already been stuck in that hot cab for about five hours, and I was over it. Next time I dig in, I'll pull that section of fuses out and inspect the connections. I'll report back.