1999 Kenworth w900 blower motor

The blow motor resistor. Dont know where the resistor is on a w9 but i'm pretty sure its near the blow motor. Check all the terminals going to the blower motor, Usually they end up getting burnt.

 

The resistor is inside the cab , on the passenger side, near the center counsel, 2 screws, almost up under the dash.If that isnt it , probably switch or the harness. Usually if the reistor goes the motor will still run on high.
Hope that helps!

 

If the resister goes, usually you only have HIGH SPEED.
It is located in a tight spot and held in with 1 screw I seem to recall..maybe the other fell out.
Pain to get at...rather tight to get a tool in there.
If you disconnect the resistor pack, you would still have HIGH SPEED with nothing connected.

I replaced the resistor pack since I only had HIGH SPEED.
The fan unit was then intermittent. On/off at random when hitting bumps.
Turns out the switch was literally MELTED at the connector.

New switch ($10) and new harness ($20) at KW...and now I have a perfect fan.

 

For anyone needing to find this module/resistor without getting raped at the dealer. It's found in various automobiles so it can be located at your local parts store or online. I've attached a couple of pictures of it too.

 

Thanks to all for the info with these. I realize the thread is a bit old, but I am having some similar issues and was looking for help, my local KW shop was not much for information.
I've got an intermittent blower motor. I have replaced the resistor and ruled this out. If I repeatedly turn the heater on and off, I can get the blower to start, and when it starts, it works on all 3 speeds. I've taken apart the blower motor "box", cleaned things out and put power and ground to the blower motor itself. The fan works every time with straight power to it. The thread I'm replying to mentions a new switch and harness, which switch and harness are you referring to? (I originally thought it referred to the freeze switch but took that out of the loop and no change without it).

Hopefully this makes sense, thanks in advance!
Adam

 

Sounds like the switch to me.

 

Ok having problems with blower motor also... no power to switch ... blower works fine when hot wire jump to it.. all fuses seem fine
94 w900