'87 Scirocco heater control problem

Dec 28, 2006 5 Replies
W

When the weather is mild, say 45 or above, moving the top lever to it's various positions does what they're supposed to. Full right, defrost (and the AC kicks in to de-humidify), second from right, floor, third from right, dash air, and so on all the way to the left three AC settings.



When it's colder, 30 or lower, no matter what position I've got the lever it, it acts as if it's in the full right position. The AC runs, the air is hot, and it comes out the defroster grills.



Between 30 and 45 (approximate, that is) it works one way or the other, but isn't predictable.



All temperatures in Fahrenheit.



Ideas?



- Bill


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P

Sounds like a temperature-related vacuum leak.

Peter Wieck Wyncote, PA

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P

Or maybe some moisture in the vacuum feed line(s)? If there is a low loop, the moisture will collect there but allow vacuum to bubble through, when it drops below 30, the moisture freezes and pluggs the line.

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W

Thank you both. Could be either one. You've just given me some direction to my search.

- Bill

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W

I don't know about your car, but when I put mine on defrost, the AC absolutely turns on. I can see the compressor start spinning and the engine idle jumps up appropriately. Perhaps the later years do something different than the '87. This is stated as being so the defrost air is dehumidified. And I can see that it works, since I have two '87 Sciroccos. One the AC works, the other doesn't. In the one that does, the defroster works much better than the one that doesn't. And this is in a side-by-side test, both cars started within a minute of each other and the environmental controls set exactly the same.

The heat works fine. It's the director mechanism which isn't working. The vacuum controlled flappers don't switch around as they should.

- Bill

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