No high on blower motor
 

I have a 1989 mercedes 300E High stopped working on the blower motor. I assume it's the resistor regulator Anyone know where it is located?

connects under the blower motor,,,other end plugs into firewall on the driver side..

two hour job, tops

This car does not use a resistor pack. Blower speed is controlled by a blower regulator, basically a big transistor that pulses power on and off under control of the pushbutton unit (PBU). Low speed is more off than on, High speed is more on than off. The PBU sends a signal voltage to the regulator indicating the required fan speed.

Do some digging in the archives and learn how to check the signal voltage from the PBU. The higher the voltage, the higher the blower speed. Make sure the signal voltage does not go to zero when pushing the high speed button. You don't want to pull the wiper motor and fan for no good reason :)

i just did my resistor the other day 1989 300ce with the 103

Attached PDF is an excerpt from the "Description of Function of Automatic Climate Control" from the 124 chassis service manual. It describes how the blower regulator controls blower speed. I haven't seen a resistor pack since I owned a 123.

i meant blower regulator, which is a resistor

Answer
 

MB# 1248202710
Fastlane: Regulator, blower
http://catalog.peachparts.com/item.wws?sku=1248202710

MB# 1248202710
Fastlane: Regulator, blower
http://catalog.peachparts.com/item.wws?sku=W0133-1598863


It mounts under the blower motor.


.

124 BLOWER REGULATOR
 

I HAVE A 124, 1992 300TE WITH A NON FUNCTIONING BLOWER MOTOR.

I HAVE TESTED THE MOTOR AND IT IS WORKING WELL.

HOW DO I TEST THE BLOWER REGULATOR?

IF THE REGULATOR IS WORKING AND THERE IS A SHORT CIRCUIT IS THERE A BEST WAY TO GO ABOUT FINDING IT?
THANKS !!!

Answer
 

If the blower motor fuse is good, and the blower motor is good = 99.99% of the time the regulator is junk.

There is NO possible way for you to repair a defective blower regulator = replace it.



FYI: ALL CAPITOL LETTERS IN A POST = SCREAMING AT THE TOP OF YOUR LUNGS on the forum.


.

124 Blower regulator
 

Sorry for yelling! My first time here.
Thanks for the advice. Much appreciated.
Since posting the problem, I tested the three prong connector behind the booster. No power when the blower switch is on. Any ideas on this one?

Thanks again.

Hmm
 

I need your VIN# to look up technical information specific to your car.

Blower motor problems
 

Vin # WBEA90D3NF201128

Thanks!

Answer
 

Look for a fuse box #51 and the strip fuse is #65 in the attached picture.

Blower motor problems
 

I checked the fuses with a continuity tester and they are fine.
I think I should give some history: The a/c stopped working at the end of last summer after I had had it repaired and some parts replaced. At the end of the winter the blower motor started acting up, sometimes on and sometimes off. I incorrectly assumed it was a brushes problem given how it would intermittently work and then stop. Now it has stopped altogether. I removed the motor and checked it, but it is fine. So the problem seems to be behind the dash given the absence of power at the connection behind the booster. Could this be a short or perhaps just bad switches? I am not sure of the best way to test these potential problems other than to open up and follow the power with a meter. Can you advise?

Again, your help is much appreciated. This is a great forum.