Not happy Fan

[LumpyVR4]

Just wondering if anyones had this issue. Recently when controlling my cabin fan speed manually, the fan only works on max. On med or low I get nothing. Dying blower unit?

 

[DOUGMO]

it will be the heater fan resistor, common issue, easy fix

 

[4piknup]

Change this to a pwm module and never have the issue again

 

[LumpyVR4]

Is there a specific PWM to use for the conversion, and where will I find the resistor assembly hiding?

 

[DOUGMO]

I haven't changed a vr4 one but they are usually on the blower box, 4 pin plug

 

[4piknup]

Is there a specific PWM to use for the conversion, and where will I find the resistor assembly hiding?

I havent worked it out, but just a small module.
Like this 10a one:
http://m.ebay.com.au/itm/350921572780

To get your speeds you would need to wire the module in (4 wires) and remove the speed knob and select varying resistors to replace the knob and give you the fan speeds.
Or mount the knob somewhere and use it.

 

[trist]

According to https://partsouq.com/en/catalog/mitsubishi/part?catalog=JP&model=E39A&code=A0285101A&category=55&classification=SNPF&group=010 the part number is MR315836. Might need someone at Mitsubishi to confirm.

I should get myself one of these as well.

Group buy?

 

[4piknup]

What is the price? Maybe I could build a couple of the pwms

 

[CLuTZ]

There's a few on ebay.com

http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313&_nkw=MR315836&_sacat=0&_from=R40

 

[LumpyVR4]

Resurrecting an old thread. I've replaced the 'resistor' which is actually a big transistor, which would lead me to believe that VR4s already use PWM for the fan control. In my case this did not fix it. Mt fan is either off, or on full, nothing in between. Anyone come across issues that haven't been the fan 'resistor'?

 

[4piknup]

If it is a big transistor, then the thing that controls it is busted. It will be a bit of a circuit board and probably on the back of the fan switch.

The links to the ebay ones are resistors.
A transistor will have 3 wires to it. Acc power, fan feed, signal (that will increase voltage as fan speed switch selects faster speeds)
A resistor will have a different wire for each fan speed and all of them at 12v (or switching each to earth if earth switched. Cant remember but i think its switched power and constant earth).

So how many wires? And its still likely to be the fan speed selector

 

[LumpyVR4]

This is a NPN power transistor in a high current TO3 case. It has two wires feeding it and the third connection is the case itself although I cannot remember which is which (probably the base is connected to the case, and the emitter and collector are wired). My guess as to why ebay sells resistors is because the US didn't get climate control which is all electronic. They just got a regular old turn speed switch like the GSR.

 

[4piknup]

Ok, climate control. now im learning. Thanks for pic.
At the transistor, you should have a wire that the voltage or duty increases with fan speed.
And a wire with 12v. And a earth.

Can I have a pic of the climate board?
It should have a tl549 chip (or similar) that generates the pwm signal. It will run on 5v so there will be a voltage divider, and another transistor to step up the voltage and
You are probably going to need a scope.. and someone smarter than me.

But can you swap in another board?

 

[LumpyVR4]

Don't have a spare climate control unit unfortunately, and I haven't had any luck finding a schematic online. All the manuals are from the US, so don't have it. I guess I'll just have to rip out the one in my car and have a poke around. With any luck it will have a problem that's a dead give away like dead capacitors or something.

 

[4piknup]

I have a dso scope. They were about $90 from ebay. Good bit of kit. About same size as ipod. Nice