Need Help With Climate Control

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Damo
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Tom wrote: Sun Mar 16, 2025 2:01 pm Did you see the video? It shows the little cigarette lighter hack I used to get 12v for testing....
Yes I did thanks! Just need to acquire one as the only cigarette lighter adapters I have are for USB.

#61

seiplej
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I took mine completely apart cleaned up the contacts. The defrost one the door was stuck and the little motor wasnt enough to open. The floor one was seized and had some some rust in the motor itself most likely from wet feet in and out of the car. But it cleaned up works. 12v on the bench tested them all.
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#62

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usury
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Some time ago I took each of my HVAC flapper door motors apart. I hadn't been getting full heat with the temp knob cranked all the way. However, I would get full heat with the defrost switch.

Turns out, the traces on the big green circuit board for the blend door motor had a crack. The motor wouldn't sweep past the crack under normal operation but would when defrost was selected. No idea why that makes a difference.
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#63

davidk86
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I’ve got a CC unit that appears to be shot. I have run all the servo motor diagnostics and they all function as mine they should and put out the correct resistance. Same with the temp and solenoid values. My cc unit does not function the defroster/footwell sliders and the temp mixing. The air speed, ac switch, and recirc/defrost switches all work.

I took off the case to the CC unit and found the c1 capacitor to be rusty and broken, so I removed and replaced. Still not getting 11 volts across the pin 5. Based on my readings here it sounds like mine is shot and I need to investigate getting a used one (since new isn’t available anymore). Some of the attached pics show what looks like brown “stuff” around some of the solder connection but it doesn’t appear rusty. Is this bad or normal?

One question I had is some of the used ones appear to have the defrost/recirc not working (but seemingly everything else functions). If mine works can I just unsolder the broken one and resolder my working switch to the new (used) unit?

Are there any other ideas/ways to test what might have gone out on the cc unit if I can’t get a donor? I haven’t attempted to fully take apart the boards yet as I’m still beginner level on soldering.
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#64

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Tom
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The brown stuff is the solder rosin -- it starts to look like that over the years. You can wash it off with rubbing alcohol, which helps you see cracked solder joints. If you don't have voltage on that pin, then either the old-school voltage regulator circuit has a bad component or something upstream of it does -- my wild hunch would be the pins that hold the boards together. If you have lots of time, I'd offer to look at it for you. I'm busy these days, so it will take a while, and my track record fixing these things is spotty -- but happy to try.

As for porting over a working switch to a replacement cc unit, that's possible for sure. The only problem is it's nearly impossible to know from an eBay ad if the problem is really the switch itself or the circuitry it controls...

#65

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Latitude48
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Sunset Porsche Parts claims they have one for $911, https://www.sunsetporscheparts.com/oem- ... 530210401c. Pelican says no longer available as does Delaware Porsche Parts. I guess I'm lucky I bought a spare in 2018 for "only" $603, and another in 2020 for $667.
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#66

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Latitude48 wrote: Fri Apr 11, 2025 12:38 pm Sunset Porsche Parts claims they have one for $911, https://www.sunsetporscheparts.com/oem- ... 530210401c. Pelican says no longer available as does Delaware Porsche Parts. I guess I'm lucky I bought a spare in 2018 for "only" $603, and another in 2020 for $667.
Hmmm.... with enough time, I'm sure a functional clone could be made for a fraction of that cost, with a microcontroller and a handful of components...

#67

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Latitude48
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Tom wrote: Fri Apr 11, 2025 1:14 pm
Latitude48 wrote: Fri Apr 11, 2025 12:38 pm Sunset Porsche Parts claims they have one for $911, https://www.sunsetporscheparts.com/oem- ... 530210401c. Pelican says no longer available as does Delaware Porsche Parts. I guess I'm lucky I bought a spare in 2018 for "only" $603, and another in 2020 for $667.
Hmmm.... with enough time, I'm sure a functional clone could be made for a fraction of that cost, with a microcontroller and a handful of components...
As I recall, Joe at FTech9 once hinted he might develop something, but this task is probably pretty far down his list of cool things.
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- 1990 944 S2 - Guards Red/Black
- 2003 Audi 1.8TQ - Denim Blue/Black
- 2003 Honda Civic Si - Vivid Blue/Black
- 2023 VW Golf R Base - Lapiz Blue/Titan Black

#68

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Latitude48 wrote: Fri Apr 11, 2025 2:17 pm
Tom wrote: Fri Apr 11, 2025 1:14 pm
Latitude48 wrote: Fri Apr 11, 2025 12:38 pm Sunset Porsche Parts claims they have one for $911, https://www.sunsetporscheparts.com/oem- ... 530210401c. Pelican says no longer available as does Delaware Porsche Parts. I guess I'm lucky I bought a spare in 2018 for "only" $603, and another in 2020 for $667.
Hmmm.... with enough time, I'm sure a functional clone could be made for a fraction of that cost, with a microcontroller and a handful of components...
As I recall, Joe at FTech9 once hinted he might develop something, but this task is probably pretty far down his list of cool things.
I'm sure he'd do a great job with them. If he doesn't, I might give it a shot at some point. With a microcontroller, the hardest part would be making sure you program it to do all the same things as the original.

#69

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Are there any custom components on it? Maybe just a troubleshooting guide would be enough. Not in my lane as I have an early car, but if someone reverse engineered the schematic, it might be possible to understand its operation and develop one. Most of the off the shelf components of this era are still available.

#70

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