E36 Bad Climate Control?

My 1999 M3 convertible's climate control has started acting up. The display of temperatures set and fan speed will dim, then go out and it will turn off the fan. It seems to also turn on the rear window
defogging fan. If I thump the dash next to it, that will sometimes get it to work again (the "bigger hammer" repair theory).
I've seen threads and web articles on replacing a capacitor inside the controller and I've got the tech skills to do that. Is that likely to solve the problem? The symptoms I've got don't seem to quite mesh with the ones shown for that solution.
Thanks!
Bob
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BobP wrote:

Actually - the replace the capacitor works because the job entails resoldering the new capacitor in. The problem isn't the capacitor - it's a cracked solder joint (which thumping the dash closes up..) Since you have the skills - reflowing the solder joints on the circuit board is a cheap/free thing to try first.
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Interesting. Hadn't read that before. Might give that a go first. Nothing to lose at this point.
Thanks.
Bob
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Heck, it worked. Just popped out the controller, took it apart, scraped through the finish over the solder, resoldered the existing capacitor. Works like a charm so far.
Bob
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In article

Just disturbing a board can 'sort' a dry joint for a while. So hopefully you've sorted it but don't get disheartened if it comes back.
--
*Despite the cost of living, have you noticed how it remains so popular?*

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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wrote:

Well considering that I've been out in Redlands a few times the past couple weeks where it's around 100* during the day, I'm *thrilled* that the A/C works again. If it dies again, well, I'll try to re-redo it. But I'm gonna hope I don't have to, regardless. :)
Bob
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BobP wrote:

The same thing works on early 90's-vintage Honda main relays, which are also prone to failure. I've reflowed the solder joints on two of them (adding some fresh solder to all the joints each time). Neither ever failed again, and one of the cars is still in service 50K+ miles later.
--
JRE

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BobP wrote:

Of course it worked... who you gonna believe? Some company or what some unknown person tells you on the Internet?
Oh - right.
You can buy me a beer sometime.. :)
(This also works on Motronic 1.1 boxes used on the E28/E24 series.. on those the output transistor leads break free - a bit of resoldering and they're good to go. Bet ModuleMaster gets $200-300 for that little trick.)
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Hey, with nothing to lose I was willing to take a flier. :)
e-beer sent.
Rancho
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