Grrr.. S40 Blower Motor Resistor

Post by **drvolvo** » 05 Jun 2009, 13:50

I have a 2001 S40. My interior blower speed does not always coincide with the setting on the dial. For example, sometimes the blower dial is set to 2 but the system blows as if it were at 4 or 5. Other times it will cycle from 3 to 5 to 1 to 2 (blowing hard, harder, slower, and harder etc but often not at a constant speed). I unplugged the connector to the blower transistor unit and cleaned out some of the dust/grime on the connections and it appeared to help for a bit. So THEN I decided to purchase a new blower motor resistor thinking that was the source of the problem. Turns out the new resistor isn't "much" better than the old one. What I do notice is that the blower works on 3, 4 and 5 holding the correct speed for the corresponding setting. But at 2, the blower speed does the same intermittent cycling to higher and lower speeds. The old resistor had been doing this 'dance' for at least 4 years. I took it to at least 3 shops, all of them staying that at the time there were no codes and that they couldn't figure out what was wrong. I was hopeful I had found a solution but now I feel like I spent money on a part I didn't need. But the new resistor helped a little bit, so I don't know what to make of my problem. The irony is on AUT the system blows just fine. Any ideas? Does something need to be reset or is something else at fault?

It certainly isn't easy getting old. haha.

Post by **vegasjetskier** » 05 Jun 2009, 14:39

Since it does fine on AUT, maybe the switch is bad.

Post by **drvolvo** » 05 Jun 2009, 14:44

When the blower changes speeds randomly you can oftentimes hear a click; other times you cannot hear any clicks when the speeds change, especially when the motor speed seems to be working. How hard would it be to replace the switch? If I just continue to live with the random switching, could it cause long-term damage of something else?

jharmo · Post by **jharmo** » 21 Apr 2011, 07:58

Did you ever find a solution? I replaced the capacitor on the resistor and had mild improvement. Then I tried a new resistor and it did nothing. Now I am wondering of the blower motor is the problem. I had the click sound as well.

Thanks,
Jeff

Post by **drvolvo** » 21 Apr 2011, 15:27

No, I gave up trying to figure out the source of the intermittent blowing and clicking. If you replace the motor (or figure out what is causing this behavior) please let me know. Good luck!