2000 Blazer, Blower only blows on 2 and 3, and not as hard as it probably should. On 1 and 4, it doesn't blow at all. I have changed the blower motor resistor and checked all of the fuses. Any other suggestions?

 

im thinking a bad switch

 

Where would I find the switch? And is it as easy to replace as the Resistor?

 

the switch is what you turn to select a fan speed, its on the dashboard right under the radio

 

The resistor pack is the most probable cause for the condition. Does it work on high? High is separate from the resistor and is run by a relay.

 

Definitely not the resistor. I switched it out with a brand new one, and that didn't fix the problem. Next item is the switch. What is that switch called? I want to be sure that I purchase the correct part.

 

It is the part of the HVAC control module, but it looks like there may be an AC Delco listing for just the switch itself.

Before you go that route, you may want to test the switch with a multimeter. From your description of the problem, it sounds like you have the manual HVAC controls (ie no auto modes). If that is the case, then here is the wiring diagram for your blower motor and its controls:

 

Thanks swartlkk! I'm a new member and was just browsing the tech section when I found this thread. For about 8 months I have had a problem with my blower fan not running at all when I switched it to high. I replaced the fan speed switch but that didn't fix it. So when I read your post about the High fan controlled by a relay, I thought "Woot! thats probably it!". Ran out and got the relay and the fan works on high now. Thanks very much!

 

Please can you tell me the location of the relay that controls the fans highest speed as I am having trouble locating it
thanks

 

Other than what is stated in the wiring diagram which is applicable for the 98+ trucks, I cannot. Sorry. You have not supplied enough information.