Rad fan control unit voltages..??

allypug

allypug

A2OC Donor
Hi chaps, been trying to sort out my non working rad fan.. voltage into the control unit at idle is around 14v, only getting 11.5v going to the fan (with aircon on) which won't spin the fan. Connecting the fan to another battery nearer 12v worked. Just wondering what voltage the control unit should be producing?
This is a replacement control unit, my original one was putting out 11.25v, which again, didn't spin the fan.
It's also a replacement fan!

Steve T
 
Sorry can't help with the voltages. Can you try another climate panel to see if that makes the fan work at the slow speed. Does the fan run at any of the other 2 speeds when the engine is up to temperature and when over heating? Always worth swapping out the fuse for a new one. Check also for contact corrosion on all the plugs on the fan and fan controller.
 
Fan doesn't run at all, if it goes over 90 degrees I put the heating on full! contacts seem fine, don't quite see how changing the climate panel would change things..
 
The climate panel gives the signal for the fan to run at slow speed whenever the climate is on.
 
it's getting 11.5v at idle with the climate on, so it must be getting this signal i guess, climate off 0v
 
You say if you put 12v direct the fan turns. Could be the panel although switching can not supply 12v to the fan. That is why I asked if you can try another panel. Change any relevant fuse and clean all earths, the voltage is dropping somewhere.
 
The control unit is receiving over 14v at idle so I would think the panel just provides a signal, not the power to drive the fan. I've measured voltage with different earths and no change there, fuse must be fine as over 14v going to control unit.
Just a thought.. I have't tried yet to see if the fan now works with this replacement control unit with the engine hot.. and if the aircon gas has all leaked out.. is there a sensor to detect this and hence not give enough voltage to spin the fan on purpose?
 
I can not say for sure but would expect if the AC was low or too high that there would be a sensor to shut the system down. I would also think this would only stop the low speed and the 2 coolant sensors provide the hot and too hot signals to turn on the fan if no AC signal.
 
so next stop then.. get car hot 90+ and see what happens! (and maybe get aircon looked at for leaks and regassed!) I see there is some sort of sensor plumbed into the aircon pipes.
 
Still concerned that with the AC on and engine at any temp the fan is not spinning. makes me think there is an unwanted resistance somewhere, I think in the supply. As you have said 12v direct makes it turn but 11.5 is not. Can you possible bypass the existing wiring from the panel to the fan controller. Broken and corroded cable and connectors have been found in the leads near to the fan controller in the past. That is unless one of the AC sensors adds resistance when it picks up an issue with the AC.
 
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