Well I know I have replaced the blower motor on that car and it was under 100k miles ago.
The normal symptoms of a blower motor is that it stops due to worn brushes. Then if you kick it, the motor starts again. In my case the motor still turns also the voltage to motor drops when it slows down, thus indicating the porcupine is not turning the blower motor on. Additionally the control voltage to porcupine is 7.2 Volts when the motor is running on high and when this problem occurs. Trampas -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Hargrave Sent: Tuesday, May 01, 2007 8:34 AM To: 'Mercedes Discussion List' Subject: Re: [MBZ] Heater/AC Blower Motor Problems Sure sounds like a blower motor to me. Thanks, Tom Hargrave www.kegkits.com 256-656-1924 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Trampas Sent: Tuesday, May 01, 2007 7:29 AM To: 'Mercedes Discussion List' Subject: [MBZ] Heater/AC Blower Motor Problems So I have been having this strange problem with the blower motor on my 1987 420SEL. Specifically the blower motor would slow down to a crawl at random times even if the switch was on high. So I initially thought it was the blower motor, but at last it was not, so I tried another blower control module (aka porcupine) which had same problem. So at this point I figured it was the Heater/AC push button unit, yes I checked fuses. Well I replaced the capacitors and resoldered the board. I still had same problem. So after much investigation I found that the power to the blower porcupine had some AC voltage on it. I thought this was unusual and check diodes in alternator and found no problems. I also checked ground connections and everything looked good. So I found that if I placed a large capacitor across the input power to the porcupine that my problems went away. I was wondering if a capacitor inside the porcupine was bad, but I would not have expected two units to have same failure mode. Has anyone ran into this problem and if so how did you fix the problem? Thanks Trampas _______________________________________ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
