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Old 11-18-2002, 04:37 PM
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pmizell pmizell is offline
Benz Zealot
Join Date: Jun 2001
Location: Houston, Texas
Posts: 838
No blow blower diagnosis

My blower motor has been working off and on for the past couple of months. From previous threads I'm trying to diagnose whether the push button control unit is faulty or if its the blower regulator. I've tried the jiggle-the-ignition-switch trick and have ruled that out.

When I voltage test the 3 wire firewall connector I'm getting 12v power from middle wire and 7v from control wire ALL the time whether PBC is turned off or on, and at any setting. (when it is not working) Of course I can't get it to run today, so I haven't been able to test current when blower is working.

When blower won't respond to PBC input I can hear the blower on a very low setting and it blows hot air out of the defrost vents. When in this mode, I get a solid LED light when I test AC fault code pin.

Also, sometimes when blower is not working while driving, it will turn itself on, without pushing any buttons on PBC.

This leads me to believe that it's the voltage regulator.... but still not sure.

Any help would be appreciated!

Thanks in advance
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi
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