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Old 07-26-2010, 05:31 PM
Jeremy5848's Avatar
Jeremy5848 Jeremy5848 is offline
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Join Date: Mar 2006
Location: Sonoma Wine Country
Posts: 8,402
As he describes it, Sixto's system is working correctly. "Low" gives you the slowest blower setting, "High" gives maximum, and "Auto" handles everything in between. It's interesting that the input to the "porcupine" blower controller is 12 Volts and ground plus a third wire from the PBU which varies from about 1 Volt to 3 or 4 Volts (I took notes on this once but cannot find them at the moment). The Porcupine (which must be a honkin' big transistor) uses the voltage input from the PBU to limit the current delivered to the blower from our friend, fuse 12 (or the external 30A strip fuse).

Incidentally, it's fairly easy to put a potentiometer in this third wire to change the control voltage manually. Push the "High" speed button and dial the blower to wherever you want it like changing the volume on the radio. Only challenge is finding a control that will go in the dash and look like it's stock Mercedes, or hiding the control so no one can see it.


"Buster" in the '95

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"Oh lord won't you buy me a Mercedes Benz."
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