onehundred80,

I have been very busy and not had a chance to build the entire circuit for testing. I hope to order the specific parts before the end of the month and build it on a breadboard for proper load testing with a 12VDC fan motor from an actual HVAC fan.

Please be patient. I am glad to see some sort of interest in this. Stay tuned.

 

Ignore a Time Lord at your own peril.
I am surprised that more people have not jumped on the wagon, they will be sorry when they see the cost of the OEM part.

 

I continue to be interested in one of the custom regulators. That said, I just switched mine out with a Hella (?) unit. I was amazed how corroded the original one was. This also included the connector plug. I'm willing to bet that a lot of regulators could be fixed - at least for awhile - by removing it and using a good grade of contact cleaner.

All and all a pretty simple procedure. The original video was Very helpful.

Thank you MMZ_TimeLord.

 

If this was corroded then my guess is that the drains backed up under the cowl and water flooded the fan area. It would not corrode unless it got wet. You did say your drains were plugged.

 

I'm sure the plugged up drains either contributed or were the cause of the corrosion. What I don't understand is that the far right drain only handles the small area for the right hood hinge. However, as long as the center one is debris free, it should be fine.

 

This area in front of the passenger also has the inlet for the heater/AC and when the drain is plugged the water can reach the inlet level and enter the car.

 

Small update:

I attempted to get some readings with my Oscilloscope this afternoon and found the output of the 'resistor pack' or 'fan controller' is DC... some noise on the line but appears to be actual DC. I could not detect any PWM signal at all up to 25Mhz, which is the limit of my scope.

So, I think the PWM should work, but I will have to consider short and open circuit protection as well. Back to research. *sigh*

 

HeHe... you lost me as soon as you said "Oscilloscope", but we all are being patient and am staying on the "list" to get one. Thanks for your effort. Cheers, Howard

 

Thanks, Time Lord!

Please sign me up for at least one, possibly two, of your new improved fan regulators.

No surprise to me that BMW and Mercedes (and Porsche, and VW) use common components. Nearly all parts like this are purchased from first tier suppliers who not only manufacture, but also do the detail design and development of similar electronic components. Forty years ago some of the biggest car makers (Ford, where I was then) would make some parts like this themselves, or possibly control the internal details on their drawings or specs, but that has evolved to the more efficient practice of just specifying functional requirements.

Thanks for your explorations!

 

are these fan regulators still for sale?

 

Time Lord is still researching the design of his replacement. In the meantime, if you need one now, these off of Ebay worked for me in both of my Crossies.

https://www.crossfireforum.org/forum...tml#post780372

 

Hello MMZ,
Thanks for the video showing the install
I'm sure it will be very helpful for the install when my part arrives.
I just bought one I found using the search feature here on the forum.

CrossfireForum.org - View Single Post - Blower motor resistor

 

Gary ...That's the one I bought. Waiting for it to arrive. Last summer in Phoenix, when temps were typically between 100 to 117, my AC blower would stop working for 10 to 20 seconds then come on again. Happened about 8 to 10 times in the hottest weather. No problems over the winter at all when I used the heater, but about a week ago when it was 92 it happened again. So I'm installing the new one and hopefully it won't just stop working when I'm on the road in 1oo to 117 this coming summer. Will keep the old one as a "maybe" spare.

 

OK I got the new Blower motor resistor and installed it today.
Took less than an hour but unfortunately it didn't correct my problem with the variable fan speeds.
The fan speed still fluctuates up and down as you turn the fan speed **** from low to high and high to low.
It doesn't seem that the fan speed goes as high as it used to either.
I'm wondering now if it is the fan speed switch itself on the dash
I'm leaving the new part installed anyway but need to investigate further

 

Thanks again to the great write-ups on this forum. I ordered this part from eBay for $33.50:
http://www.ebay.com/itm/310843351770?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
The Crossfire is not in the compatibility list but I used the part number and it fit perfectly. It came with 2 red wires - short and long. I used the long one.

I think someone else got one for less than $30 but I liked this in the posting "Effective June 23, 2014: This item is backed by a manufacturer's 10 Year Warranty. In the event this item should fail due to manufacturing defects during intended use, we will replace the part free of charge (excludes shipping charges) for the original purchaser.

Because of the great post with the video, I was able to do this change out in about 30 minutes. Thanks again.

 

Like others, I was the victim of the HVAC Fan Blower Resistor Regulator. Thanks to to great video and owner posts, I replaced the Regulator and Cabin Air Filter for $44.37 (delivered) in less than 20 minutes. I used the MB part cross reference and ordered the Regulator on eBay. The replacement Regulator I chose came with a 10 year warranty and cost $27.39. This is my happy face!

 

Post #55 took 30 minutes to instal the part, post #56 took 20 minutes. When the time comes to instal mine it'll be done in seconds. LOL
Seriously I got one for a back up, just in case.