Vent fan problems

donf · Post by **donf** » 25 Jun 2016, 21:03

2005 S80.
Problem started with erratic vent fan speed, could get fan running by pulling and removing fuse but eventually nothing. So I removed the blower motor (not quite as easy as those write ups suggest but doable).
Now my question is how do I determine whether my problem is my fan or the resistor? I had planned to open the the resister up and look for evidence of overheating since my cabin filter was at least 5 years old but the filter didn't look too bad and I can't get the resister open anyway. (Had a similar problem on my MDX last summer, lots of write ups and an easily soldered 75 cent piece got me up and running in an hour. I was hoping for a similar experience. Yeah, right.)
As an aside, my S70 has 230,000 miles on it and the original fan works great so I'm biased against the resister - but then that hasn't been replaced on that car either ........
I really don't want to buy both parts unless I have to. There seems to be scant mention of these parts on the forums, unlike other issues which have a huge number of posts.

Any advice/help would be greatly appreciated.

Post by **oragex** » 26 Jun 2016, 04:27

The resistors do go bad. Usually it shows as not the right speed. But I don't know a way to check them with a multi-meter.

At 230000 miles, the motor brushed can be worn - removing the bottom motor cover gets access to them. The shaft bushings are also prone to seizing (check it turns easy by hand). A used motor is not expensive off Ebay (look for a unit which is not rusted on top of the fan blade part)

Post by **oragex** » 27 Jun 2016, 05:15

donf · Post by **donf** » 27 Jun 2016, 17:56

Thanks.
Actually the 230,000 miles example is on an S70 - still working but I'll replace ita th the first sign of problems - the post was about a 70,000 S80, which is why I was thinking that the motor should still be good but I'll just hook it up to 12 volts and see if it spins freely.