I had this some time ago. Make sure to replace your cabin air filter on a regular basis. About every 18 months because they sure do get dirty and that is dirt that's not getting into the car. FCPGroton.com had them at a decent price.

The transistor can be bought from the dealer for $100, or do a search on s40concepts.net. The assembly the dealer sells is built around a generic transistor that can be picked up from Radio Shack for about 7 bucks. If I recall, it just needs to be soldered onto the board. I don't recall all of the details. I was looking into this two years ago, then I changed the filter and the issue went away.

mormit
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02 S40 , 98 V70 T5 Koni FSDs, IPD swaybars and HD Endlinks, 85 245DL 278,000mi V15cam It takes a licking and keeps on ticking

klausc
Thanks for your response. Yea, its always done that. I've owned it since 04. But now it pulses all the time. It doesn't matter if the car is cold or fully up to temperature. It continually changes speeds, mostly in the lower speeds. It seems to be ok at high speed. Any other ideas would be appreciated.

Sharpie

When you initally turn the car on, the blower will go to max speed for a few seconds while the electronics are checking everything out. This is normal.

Klaus
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Volvoless. Sold the R. There is now a void...