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Porsche-O-Phile Porsche-O-Phile is offline
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Join Date: Feb 2004
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This stuff is so fascinating to me. Bummer the 944 unit won't work in native form. I'm a bit surprised (though not entirely) that Porsche didn't just use an off-the-shelf available part and instead went through all the trouble and expense of having a "mostly the same" unit created. Not necessarily the way I'd have done things. . .

When one looks at the two units side-by-side (especially in the top view) there are pretty obvious differences to the solder patterns. This would lead one to believe the internals are different, although it doesn't rule out the possibility that the physical locations of individual resistors, I/Cs, etc. simply moved around to alternate locations within the assembly from one version to the next. . . Wayne has the wiring diagrams, so that's the Rosetta Stone of this whole thing.

I agree with Wayne that simply plugging in the 944 unit would be reckless and could create some unintended consequences, maybe even bad ones. Not something I'd risk. If there were more market for 959 air conditioning consoles (since the part is NLA), I might even feel compelled to create a signal translator that would go between the 944 unit and the 959 harness, enabling those poor stricken 959 owners to simply source a 944 unit, plug it into the box and live happily ever after (as if they weren't to begin with, being owners of 959s and all. . .)

Electrical diagnosis is not difficult but it can be a big PITA. I'm going through this on my own 911 right now with much simpler (and fewer!) circuits. Look forward to seeing how this all plays out!
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'74 911 Targa 2.7 (in storage, hoping to finish "someday"), 2001 Mercedes SLK 320 (with a few AMG fun bits), '85 BMW K100, a few surfboards

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Old 10-29-2007, 03:37 PM
  Pelican Parts Technical Article Directory    Reply With Quote #7 (permalink)