If I have more time later, I'll take a look at what might be causing the issue, but for now, I figured I'd get you the schematic.

 

Then dash switch is new , fuses are good . I checked and cleaned the resistors . Then I went to a parts store and they let me borrow a new resistor to try . A new resistor did not make any difference , so I did not buy it . Im not sure what to do now .

 

Could be the relay. Again, I haven't had the time to dig in and really analyze the schematic I posted earlier.

 

Well , here is what happened .

After a crappy day at work , I was diving home on an alternate route . Notice a sign that said " Pull A Part " . So I decided to check it out . Huge salvage yard . All vehicles are raised up off the ground , and there is NO mud/dust ,SUPER cheap prices !!! WOW . Entire salvage yard paved everywhere . 30 day unconditional return on all parts including electrical ! So I grabbed that little silver relay box off a junked blazer ( I posted a pic a few entries back ) to see if it would help . What do ya know . $2.50 and my heater fan works on all settings now .

Now that its fixed , its time to ride !

 

I was mistaken then. Glad you got it figured out!

 

Hey guys, I've got a 2001 chevy blazer 4.3 V-6 same problem, heater fan only works on high. So far I've replaced the fan blower, the switch on the dash, and still blows only on high. I'm pretty good with doing my own repair work been wrenching on cars and trucks with my ole man since 1968. I can't figure out this fan blower I'm dumbfounded, any suggestions would be greatly appreciated.

Peace Droidxusa,
aka Joe.

My problem and current situation is same as above, should I go ahead now and replace the relay. Could it be that simple of a fix, I will try this and see what happens. Thanks for any replies or suggestions.

Peace Droidxusa.

 

The vehicle in question is much older than yours, but the advice is still sound. The blower motor resistor is at fault. This is well documented on the forum as a search for "blower+motor+resistor" will show. Do some reading up. It quite easy to change out. Of course, if you have the electronic climate control (numbers around the temperature dial and not just blue/red), then you don't have a blower motor resistor pack.

 

Thanks swartlkk, when I tried searching earlier today nothing was coming up even under advanced search, so I tried your suggestion above and found that many of us have had this resistor go bad.

Again thanks for listening/reading about my electrical problem. I replaced the blower relay and fan still only works on #4 speed setting, going back to advanced auto to get the resistor now will install it tomorrow. And yes my switch is just blue and red.

I'll report back tomorrow with an answer of yes the resistor was bad or no its something else.

Thanks everyone for looking at my post.

Peace droidxusa.

 

Thanks for everyones suggestions!

swartlkk, kudo's to you bro my blower speeds are now working on 1,2,3 & 4 this is after replacing the blower resisitor, for the hell of it I also replaced / kept the new blower relay. It seems that the blower settings for defrost & floor have a vac leak somewhere, as I only get air blowing thru center dash vents.

Lo and behold, while looking under the hood I found a dry rotted 6" hose that wasn't plugged into anything. After reading other post's over the last few days found out that the 6" vac hose should be plugged into the vac canister under the abs.

see this thread post #9 has picture of where this vac line goes:
https://blazerforum.com/forum/2nd-ge...no-heat-14749/

Hope this helps someone, I know how long it takes reading up & searching posts.

Now I can move onto next project, that is getting 4-wheel drive to engage from 2-wheel Hi to 4-W Hi & 4-WLo, will search for a thread with info for trouble shooting this. I only have 2-W Hi right now!
If anyone has a link to a thread please PM me or post a link for it.

Peace Droidxusa,
aka Joe.
2001 Blazer 4.3 V-6 4X4 Dig it man, Dug man.