Brunner Fridge Fan Speed Control (1 Viewer)

[sallylillian]

I have this in my van and I suspect it was me who blasted too hard with water as the fans stopped working. So I went to the local (here in Silves) PC shop and bought what were in terms of structure the same fans. BUT they have red and black leads plus a yellow and the originals did not have 3 wires. I connected the red and black as + and - respectively and the fans work. However switching to manual on the control panel does not cause the fans to go to high speed. There is a green wire in the cable from the controller that goes to what looks like a diode but I assume is a temp sensor and this connects to the reds. So I wonder if I need to connect the yellow somewhere, assuming it is some sort of signal wire?
Any clues?

 

[Richard n Ann]

Maybe it's to a hall effect sensor inside the fan. These are there so the driving electronics know what position the rotor is in. But if it's working without it's not needed in your case. I would measure the voltage being fed to the fans and see if it changes on high and low speed settings.

 

[tonyidle]

I have this in my van and I suspect it was me who blasted too hard with water as the fans stopped working. So I went to the local (here in Silves) PC shop and bought what were in terms of structure the same fans. BUT they have red and black leads plus a yellow and the originals did not have 3 wires. I connected the red and black as + and - respectively and the fans work. However switching to manual on the control panel does not cause the fans to go to high speed. There is a green wire in the cable from the controller that goes to what looks like a diode but I assume is a temp sensor and this connects to the reds. So I wonder if I need to connect the yellow somewhere, assuming it is some sort of signal wire?
Any clues?

The yellow is a speed output from the fans so the PC can read how fast they're spinning. It shouldn't be connected to anything in your application.

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[sallylillian]

OK that is now clear, if the speed is controlled by voltage what would be the low speed volts and high speed given its a 12vdc fan?
Thanks Tony and Richard for quick feed back.

 

[Richard n Ann]

Something like 12 - 13.8v will be high speed depending whether you're on hook up. And something like 6 - 8v for slow speed will be noticeably slower. My fridge fans are wired in series so always get about 6.5v each and they are slow and quiet.

 

[sallylillian]

Something like 12 - 13.8v will be high speed depending whether you're on hook up. And something like 6 - 8v for slow speed will be noticeably slower. My fridge fans are wired in series so always get about 6.5v each and they are slow and quiet.

Thanks, I think the sensor that is wired on the frame with the fans maybe screwed too, as adjusting the temp screw on the control box does not seem to have effect. I have a reading of 36° from a separate sensor up there but the control box displays the red LED (high speed indicator) when on auto how ever I adjust the screw and I should be able to set it at 50° for high speed, so will just be satisfied with the fact that I now have extraction until I get home. I think I will get @funflair CBE solution when I get home, unless the sensor is an easy replacement.

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