Final Stage Resistor fix DIY

[MINIz guy]

I'd like to chime in that this free fix only worked for 2 years. I posted back in 2010 that it fixed my intermittent fan speed oscillation. Then, in late 2012, the FSR completely went out and there was no fan at all. Still a great fix, and if the new FSR has the same symptoms, I'll be soldering that one too.

[HEISING]

Hi guys. Glad you all are benefiting from this easy fix! The longevity of the fix will depend a lot on the re-soldering quality. The semiconductors get really hot, and the legs will re-open again if not soldered carefully. One good solution to add life to any FSR is to have the blower running "halfway up" or more. The FSR block is cooled by air running over it, when your climate control fan speed is slow, the FSR block will tend to get hot.
If you want to use a solder with a higher melting point (Silver Solder) that's OK too. Lead free has a higher melting point also, but a little tougher to flow.

[Doru]

I wish I knew about this thread earlier. Well, it's bookmarked now.

[z168]

awesome post - I now have this issue. I will try at it later today

And here is a DIY of how to remove it (just so we have it all in one place)

[z168]

My blower went dead in the morning and suddenly worked flawlessly towards the afternoon. Ordinarily I would let it be for a while but with the heat I had to get a move on

so I got around to removing the FSU. 3 minutes to remove the panel and get to it and another 15minutes trying to remove the socket. and after about 30 minutes carefully removing the insulation I get around to solder it. its not my best work, but it will have to do





so after plugging it back in of course it worked. but now as I write this I just realized I didnt put any form of silicon or gasket maker in to cavity. Is this a necessary step or can it be left as is? I did cover it with electrical tape but I didnt give it much thought till now

[HEISING]

Hello Z168. Glad to hear it worked. The soldering needs to be cleaned up and flowed properly though, or you may find it will fail soon again. Sometimes scraping the existing copper traces helps the new solder to flow easier. I see the center pins have almost no solder on them. Make sure the pads are cleaned and flow solder to them. Liquid Rosin Flux really helps this process. These units get so hot, any soldering errors will quickly show in premature failure.

I didn't seal my unit back up. I just left it open. This is up to you to decide.

Good Luck!

[z168]

My soldering gun gets a little too hot for comfort so I had to be quick. Im afraid I might fry the circuit board. I should probably get a small iron instead

Thanks again Heising!

[ChevDog1]

Well, it's been about a year, and mine has quit again. The last time, it was just a little corrosion on the plug that connects to the FSR. I have to pull it out when I get home tonight and see if I have the same problem again, or if I have to get out the soldering iron.

[z168]

Mine hasnt failed but it might be a good idea to buy a replacement for it just in case this happens again this summer

[ChevDog1]

Well, I took it out last night. I tried to remove the potting material, so I could re solder the connections, but the potting was so hard that I was afraid of damaging the unit in trying to remove it. After about an hour of scraping, chipping, cutting, etc, I finally gave up. I put the unit back in the car and planned on buying a new one today. When I started the car to move it after I had finished - it was working again! So far today it hasn't failed yet. I guess I'll just wait until it dies again, and then buy a new one. Are these available at auto parts stores, or are they dealer only?