blower motor 75' KW 2-speed


Well-known member
Our blower motor quit the other day and as wet as it is around here the truck fogs up pretty quick!!! So needed to got it switched out quick!
Looked around online and wasn't coming up with much so went to the local KW dealer and they came up with a new motor from part numbers that had been superseded a dozen times ;) The new motor is only a single speed but for now that doesn't matter if it gets to where it's too noisy running at full I'll either rig a resistor in there like the latter trucks use or throw in a variable DC chopper board as I have plenty from other robotic projects :)

The blower wheel is also different, it is at least an inch longer and should push more air as the housing has the room for it... I'm guessing someone changed it out years ago with a different from stock wheel/motor for some reason???


Forgot to take pics when I got done because it was raining pretty good and I just wanted to close things up. But it blows air good now so hopefully nothing else goes kaput for a while :)

Steve Frazier

Staff member
I plugged the number on the top photo which I assume is the bad one and see one for $109. I could be wrong but I thought blower speed was controlled with the switch and resistors rather than internally in the motor. I'd think if it were internal it would require one wire per speed, or in the case of a 3 speed, 3 positive wires and the ground or 4 total.


Well-known member
Nice work Ron and what Steve said ! In cold weather I want all 12 volts going to the fan motor and throttle peddle mashed to the floor on the GMC wrecker to warm up the cab . LOL! 😄


Well-known member
Most of the later trucks I have seen all use resistors that are cooled in the airflow of the system, this old motor has two separate coils and hence the two wires r/or for high/lo speed with an internal ground. The replacement motor(sorry I forgot to get a pic of it) has a black(ground) wire and a red(+12vdc) wire which I actually had to reverse to get the right rotation. Shaft sizes looked the same between the two motors but I didn't actually measure them...

Yes Steve, the number on that first pic is the old one... I searched and found it instock a few places too but when tried to order it wasn't really in stock ;) dealer was 88bux for the new 1 speed and then about 20 for the new metal squirrel cage

Also I don't think this was the original stock motor just because of the plastic wheel and the fact that it was at least an inch short of fitting snug in the housing which is why it probably never really blowed very good...

Truckstop, yeah that resistor/switch would be the simple thing to do :) We'll see how this works... sometimes it's like pulling hens teeth to get an ok to do something to things that 'work' in order to make them 'right' ;)