so the heater/ac blower only works on high now... could this be a fuse or something? the whole controller was replaced about 2 years ago, could this be the problem again?

Moved to electrical, and it sounds like the blower motor resistor possibly?

Prolly Controller again. I used to go through those alot on my old truck.

I had this happen on my Yukon. Not sure what your controls are but my Yukon has the auto temp control system. It got stuck one day and wouldn't stop blowing, even when you turned the key off. Pulled every fuse I could find and even when I found a fuse that stopped the fan it started right back up when you put the use in. Ended up disconnecting the battery and it reset something, been fine for 2 years now.

sounds like a blower motor resistor to me.

As far as i know low, med and med-high all run through the resistor. There's just less resistance as the blower speed increases as the blower sees a higher voltage with each turn of the switch.

High speed bypasses the resistor and kicks on a relay which puts direct full voltage right to the blower motor, giving you maximum speed.

sounds like a blower motor resistor to me.

As far as i know low, med and med-high all run through the resistor. There's just less resistance as the blower speed increases as the blower sees a higher voltage with each turn of the switch.

High speed bypasses the resistor and kicks on a relay which puts direct full voltage right to the blower motor, giving you maximum speed.


so is the resistor serviceable? if so where do i find this little jewel?

Yep its likely the resistor. I couldnt tell you where its located tho.

Yep its likely the resistor. I couldnt tell you where its located tho.

well i sure would like to replace a resistor rather than the controller.. surely someone knows where it is...

I have the same problem.
Hope to hear the solution.

Brian

take the glove box out and you will see it in the back on top of the air box... it's a PITA to get out if I remember .. I had the same problem about a year ago.. the switch also goes bad you can get it from napa.. not that bad in price

Johnny

resistor is easy to take out there is a big plastic cover under the dash runs from pass side to middle then you will see it 2 bolts and a plug and its out

new ones run 20ish

so is the resistor a napa part as well?

take the glove box out and you will see it in the back on top of the air box... it's a PITA to get out if I remember .. I had the same problem about a year ago.. the switch also goes bad you can get it from napa.. not that bad in price

Johnny


Definately a PITA, been there done that.

I just did the resistor in mine last winter.
Same issue, only worked on high.
Out seemed like more of a pain than going back in.
you pull the glove box out, then you will see the relay for high, and a plug.
unplug them both, unbolt the bracket and set aside, then there are two bolts holding the resistor down, make sure you unplug the resistor before unbolting it.
from there hold your nose just right and it slides out.

Yes the resistor is a napa part aswell

thanks for the help guys, i can see the resistor back there, doesn't look too bad to do.

i got the resistor last night at advance for $16.99 pn RU866 (same # at orielly)for the sake of someone who searches for this in the future... thats what these things are about right?

i'll post up how the r/r goes and if it fixes the problem..

resistor is easy to take out there is a big plastic cover under the dash runs from pass side to middle then you will see it 2 bolts and a plug and its out

new ones run 20ish

He has a 95 GM vehicle, not the Classic!

the resistor fixed the problem.. it is in fact behind the glove box on my truck. just a little bit of a PITA to get to, had to take the mounting bracket for the relay off, unplug it to get it out of the way..

its definately sound advice to unplug the blower resistor before unbolting it. the biggest problem was getting the resistor reinstalled without bending or breaking it. its one of those square peg and round hole situations..

Thanks for the help guys, definately saved some time and money once again..