Hi, everyone,

My mother has a 2000 Blazer. Recently I heard a sound that made me think the fan blades were rubbing. It only happened occasionally, then increased to the point where it would be constant, then suddenly get loud and I think jammed as the sound would suddenly get very loud but no air blowing. Once you turned the speed down to either 1 or 2 it would stop. At 1 or 2 it isn't blowing at normal speed, but you would get a decent amount as long as I'm driving quickly.

I replaced the blower. The first ten seconds it blew correct at all speeds. Then it started making that rubbing sound, then a huge clunk so I turned it off. Now it wouldn't even give me the trickle the original blower did. Pulled the new blower, the fan blades had shattered. I mean at least 20 pieces. I put the old blower back in and the low blowing at 1 or 2 returned, the rubbing at 3 or 4 with the jamming happening within 20 seconds came back.

At higher speeds the fan blows faster. At interstate speeds the 2 setting almost reaches what a working 2 should be. As soon as I stop, barely a trickle.

I'm so confused with this. It seems like the blower is bad, but it still puts out a trickle. I can't figure out what's causing the rubbing and what caused the new blower to shatter its fan. When I pulled the blower I cleaned out all of the debris present, but there wasn't that much.

I did try Googling and searching this forum, but all of the articles and posts are about the air getting warm at speed or the fan slowing at speed which is the opposite of what's happening to me. The air is ice cold, just not moving.

Any help would be appreciated. It's getting very hot in the truck and my mother isn't in the best of health, I'm worried she may pass out from the heat. It's hot enough that when I'm driving in the daytime I'm pouring sweat, and now wear workout clothes when I'm in the truck.

 

I've had some bad connections with my blower motor before. With the aftermarket ones I've gotten, the connector is pretty tight, and has to be just right to plug in without bending the tabs and having a bad connection.

Not sure what would cause the fan blades to shatter, that seems pretty strange to me.

 

I'll check the connectors here in a bit, thank you.

The fan blades shattering is bizarre, especially since the original isn't even cracked. I wonder if the blades on the original are tougher,

 

Might just be a coincidence. Like, that new one had a bad run of blades at the factory or something. Seems kinda far fetched, though. I hate throwing money at stuff, but as cheap as blower motors are, I might just try one more and see what happens. Double check that there's no debris in there. The cowl screen on mine is all broken, and leaves and crap get down in there

 

Blower fan is a simple DC motor. The speed is controlled by an external set of resistors. I found a diagram over the network (I hope that's a good one):



Hence Your replacement fan blower was running at a correct speed, I'd say there's nothing wrong with Your connections. The old one seems to be having some conductivity issues (worn off brushes maybe?), so it doesn't run at a desired speed.

The replacement You put probably had a mechanical defect - especially if it was a cheap replacement - or something just suddenly hit the propeller and damaged the blades. It is impossible to destroy the propeller in a such way with an electrical issues.

 

Thank you for the diagram! Sorry for the late replies, had some sick family members to take care of.

I'm going to replace the blower here shortly. I'll update with the results.

 

Finally able to swap out the blower again and it seems to work. I haven't tested it on the #4 fan speed yet, but #3 works and I'll be okay with that for now. Good news, at least.