MOSFET resistor need help....

[hornhunter]

mosfet resistor

Hello respective members of the forum,
I have one problem and hope that anyone here can help me solve it.
My problem is about automotive Mosfet resistor/regulator for the blower motor for mercedes E class. This resistor is dead. I am interested what type of MOSFET resistor is it and is there a replacement for it. The purpose of that dead one is to regulate the speed of the fan. It has 4 connectors. I will upload the picture. Help of anykind is welcome. Thank You all.
I know I didn't said much, please ask whatever is important.
Don't know how to find this part among thousands electronic components.

 

[mpathma]

mosfet as resistor

Hi,

How you decided that this is for speed regulation?

M.Pathma

 

[banjo]

mosfet as a resistor

Are you sure this is a resistor? I think you are looking at MOSFET itself. MOSFET is Metal Oxide Semiconductor Field Effect Transistor. However, lots of people say MOSFET transistor.

This MOSFET is probably run as a chopper to create current pulses that speed control the fan. Unfortunately, this module was most likely a custom part for Mercedes. Usually these modules contain several MOSFETs in parallel attached to a metal plate as a heatsink and then covered with epoxy for moisture sealing and to help with heat.

 

[zenia]

darlington transistor mercedes blower

The register is blower control module.Advise you change a new one beacause it is hard to change the electric components in the blower control module .Even if you open the module may find it could broken it to change the MOSFET in the module.

 

[hornhunter]

resistor for mosfet

Thanks guys...
You are all wright, so I have to give a large amount of money for it...
I am sure it is used for the fan speed regulation...

 

[Awarapunshee]

mosfet blower motor resistor

Thanks guys...
You are all wright, so I have to give a large amount of money for it...
I am sure it is used for the fan speed regulation...

If this module is faulty, and you have to anyway through it away, and you have the time, then open this module. If there is hard epoxy in it, just heat it and extract just like the Archeologist do, heat again if it becomes cool. When all the components are exposed (If this modules contains many components), you can check which is faulty.

ENJOY!

 

[hornhunter]

using mosfet resistor

Yes it is hard epoxy inside.
I just learned that it is not MOSFET but bipolar, in a darlington configuration, some guy told me on MercBenz forum

I will upload picture of the part a little bit later...

 

[hornhunter]

mosfet chopper for fan

I took the Awarapunshee advice and this is what I have found below.

The input pin is connected to the metal plate, and the output connector together with 2 control connectors are standing on something like resistor plates, and when You want to speed up the fan the voltage on this control pins is droping and the fan speeding. This output conector is ground for the fan and the + connector is connected directly to the fan.

 

[Awarapunshee]

how to find a broken mosfet

What I guess is, this unit is not repairable. As no discrete components for the service availiable.

 

[hornhunter]

pic mosfet fan control

Must agree with You...
Consider this theme closed.

Thanks guys for all your help...