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1997 S500V
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Discussion Starter #1
Hello,

I sure this topic has been covered but I just replaced mine today and had a little spare time to document this simple repair. It's a 10-15 minute job if you take your time, so simple a caveman can DO IT! I am not an expert but discovered this worked wonders for my car's A/C!

I got my blower regulator off eBay for $75 with a supposedly German OEM supplier: Hamburg Technic. I called stealership and they quoted $292 and $399 for two brands. I didn't ask but assume it's Bosch or equivalent. Autohaus has German name brands for ~$170-230 so I took a chance with eBay...

Tools needed: Philips screwdriver #2 and Torx-20 driver. That's it!

Symptoms: very weak air flow especially though out the day in Dallas, TX heat. I noticed air flow getting weaker in a period of a month. So I broke out my Fluke DVM and only measured 2-3VDC across the blower terminals. If your press REST on the climate controls for 10sec. you get into the diagnostic mode. I pressed the left AUTO button to cycle up to step 10 then adjusted (+-) fan buttons. On MAX, I only measured 4VDC. First start up in the morning yielded me 7VDC but still didn't flow a lot. When I commanded 1 or 2 bars (MIN), I got a whopping 1VDC.

So below are the snapshots with comments, hopefully I covered everything and didn't leave out anything critical...
 

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1997 S500V
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Discussion Starter #2
More PIX...

Finals comments: I believe the former owner must have replaced the regulator since it's a BEHR made in France and had thermal paste applied sloppily all over the place. I recommend using bare minimum. Notice how some paste was over applied to the bottom heatsink with no contact to the blower housing thus acting as an insulator.

If this lasts a few years, I'll be happy vs. $399...the amount of air being moved in the passenger cabin is like a sh*t storm...WOW...no need to block off the back and passenger side vents anymore to get airflow.

This repair is an extremely welcome need in my part of the woods!

Best of luck,
Mo
 

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1997 S500V
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Discussion Starter #3
I forgot, you'll also need a 13mm wrench for the battery terminal and radio code to unlock the secuirty feature...
 

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1997 S500V
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Discussion Starter #5
Well, the eBay source Hamburg Technic regulator failed 100% and left me with absolutely no airflow during stop and go on the highway, 105F yesterday. Sucked big time so I ordered a KAE version from Autohaus...

The eBay source is offering to send a replacement but I'm not so sure anymore about these no name fan regulators. $75 makes it too attractive...(*&^&[email protected]

My old BEHR still works but low speed is all it's got...
 

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Well, the eBay source Hamburg Technic regulator failed 100% and left me with absolutely no airflow during stop and go on the highway, 105F yesterday. Sucked big time so I ordered a KAE version from Autohaus...

The eBay source is offering to send a replacement but I'm not so sure anymore about these no name fan regulators. $75 makes it too attractive...(*&^&[email protected]

My old BEHR still works but low speed is all it's got...
Hi MOS500,
Thanks a million for the pics and process notes. I need to replace my blower regulator, too. I already replaced the In-Dash control module for the Heater/AC... still no fan response - so blower regulator is next step.

I was also going to pickup the parts on eBay. Are you sure, yet, that it was the eBay part? Where do you recommend we get the Fan Regulator and Thermal Paste?
 

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85 300SL Euro,97 SL320,95 S420,07 S550
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That was faster then expected usually they last up to 2 month.
Behr is not a french company but the OEM part for Mercedes,you can find sometimes one on Ebay ,I just bought a new one for $150 otherwise the dealer price is $250 but worth the money.
How I know,I tried twice one of the cheaper ones all from Germany they all didn't last.


I just saw you ordered the KAE,it's made in Berlin Germany it lasted 2 month .
My indy warned me before I bought it but I wanted to save money.

Good luck let us know

Ulf
 

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1997 S500V
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Discussion Starter #9
That was faster then expected usually they last up to 2 month.
Behr is not a french company but the OEM part for Mercedes,you can find sometimes one on Ebay ,I just bought a new one for $150 otherwise the dealer price is $250 but worth the money.
How I know,I tried twice one of the cheaper ones all from Germany they all didn't last.


I just saw you ordered the KAE,it's made in Berlin Germany it lasted 2 month .
My indy warned me before I bought it but I wanted to save money.

Good luck let us know

Ulf
Well, my BEHR unit sounds German but the sticker says Made in France. I just got my KAE version from Autohaus and it has "very efficient" copper based paste instead of the white thermal paste. It is already applied so you just have to mush it down. It also comes with a blue cloth to wipe down (polish) the blower housing heatsink. Hopefully this one will last a while. I found no less than 5 versions available: BEHR, KAE, Bosch, Genuine, and Hamburg Technic. I personally think there are only 2 versions based on the footprint and housing. Typically, one or two major suppliers with different stickers.
AllPartsExpress - quality automotive parts for less!
 

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1997 S500V
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Discussion Starter #10
That was faster then expected usually they last up to 2 month.
Behr is not a french company but the OEM part for Mercedes,you can find sometimes one on Ebay ,I just bought a new one for $150 otherwise the dealer price is $250 but worth the money.
How I know,I tried twice one of the cheaper ones all from Germany they all didn't last.


I just saw you ordered the KAE,it's made in Berlin Germany it lasted 2 month .
My indy warned me before I bought it but I wanted to save money.

Good luck let us know

Ulf
Well, my BEHR unit sounds German but the sticker says Made in France. I just got my KAE version from Autohaus and it has "very efficient" copper based paste instead of the white thermal paste. It is already applied so you just have to mush it down. It also comes with a blue cloth to wipe down (polish) the blower housing heatsink. Hopefully this one will last a while. I found no less than 5 versions available: BEHR, KAE, Bosch, Genuine, and Hamburg Technic. I personally think there are only 2 versions based on the footprint and housing. Typically, one or two major suppliers with different stickers.

AllPartsExpress - quality automotive parts for less!
 

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Believe me Behr is the original one ,and like I said I had used the KAE and my Indy ,who is German,told me that they don't use it anymore because of the high failure rate.
Mine KAE lasted 2 month.

Good luck

Ulf
 

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1997 S500V
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Discussion Starter #13
zone - heres is your answer

MOS - by measuring the voltages, is that an indication the regulator wasnt functioning right?
z168, yeah, that's correct..command a voltage and make an actual measurement at the regulator/fan. My symptom at commanded full speed (12V) only gave me about 3V at the regulator which is equivalent to very slow fan speed.
 

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Gentlemen: I'am having the same problem on a 96 140(medium speed is max) Has anyone found a regulator that works long term yet, not from a dealer???
Thanks for any info.

Ron
 

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Discussion Starter #15
My KAE regulator has been working fine since July1 in the TX heat. $170 from autohaus. I also have a replacement cheapo ebay $75 version on standby......
 

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1998 S500
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My KAE regulator has been working fine since July1 in the TX heat. $170 from autohaus. I also have a replacement cheapo ebay $75 version on standby......
It is possible that a hot environment may actually be less stressful on the regulator as it is likely that your blower will be operating at a higher speed in that situation. When the blower operates at a higher speed, there are two things happening that will extend the regulator life. First there is higher air flow which will serve to keep the regulator temperature down which is good for life. And the voltage drop across the regulator will be less which will reduce the heat dissipated across the regulator.

Conversely, a slower setting of the regulator will make both situations worse. Not a great design but that's the way it is.
 

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1999 S500 1999 S420 1994 S320 1994 E320
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Has anyone found a regulator that works long term yet, not from a dealer???
Thanks for any info.

Ron
Hamburg technic:thumbsup::thumbsup::thumbsup:



Hamburg technic vs Bosch



1 year,daily driver,$ 75.00 on Ebay

3 times stronger then the old Bosch
 

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W140 Mercedes 500 SE, 1992, European, 410.000 km
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Someone correct me if this is not right:

Max setting of the blower on the A/C panel is not always "the real maximum". The real maximum speed of the blower will be achieved only if the preset temperature in the cabin is minimal or relatively low (15 °C for instance) and if the real temperature in the cabin is high (40 °C for instance). At least that's how my HELLA regulator works and the original one works also before it died.

In another words, if the cabin temperature is relatively low, then max blower speed is less then if the cabin is hot.

So, is this true?
 

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Discussion Starter #19
Someone correct me if this is not right:

Max setting of the blower on the A/C panel is not always "the real maximum". The real maximum speed of the blower will be achieved only if the preset temperature in the cabin is minimal or relatively low (15 °C for instance) and if the real temperature in the cabin is high (40 °C for instance). At least that's how my HELLA regulator works and the original one works also before it died.

In another words, if the cabin temperature is relatively low, then max blower speed is less then if the cabin is hot.

So, is this true?
True if your HVAC is in AUTO mode. Go into the diagnostic mode and command 12V or all 7 bars full fan speed and DVM measure to see if your regulator is providing all 12V to the fan motor for verification. If it gets significantly less than 12V, then your regulator is dying.
 

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True if your HVAC is in AUTO mode. Go into the diagnostic mode and command 12V or all 7 bars full fan speed and DVM measure to see if your regulator is providing all 12V to the fan motor for verification. If it gets significantly less than 12V, then your regulator is dying.
I went into AC self diagnostic mode and put fan speed to MAX, but I can hear that this is not what it was few months ago when I replaced blower regulator, thus I do not need to measure voltage at the blower at all. I would say it works with 75% of power.

But I also noticed that refrigerant pressure temperature was not under 6 °C during the test. Maybe this influences the fan MAX speed also?

I paid 215 EUR for HELLA regulator, it seems that I will have to buy BEHR at the dealer. is it necessary to use the dielectric paste only at the contact REGULATOR-HOUSING, or at the entire regulator's back side because the new regulator is larger than the original one?
 
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