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Discussion Starter #1
at this point im ready to sell my s60r...

i was in the cities the other day and my car started to over heat. the fan does not appear to be working...

on the 2006 model that i own, the fan speed regulator is on the motor itself not beside it... i simply need to know, what is the voltage i should expect on the violet wire at the connector on the passenger side of the radiator fan housing? cold, i dont seem to see any voltage. at high temps, it puts out 3.3v (if i recall correctly). is that the right voltage? am i low?

anyone by chance have a fan for sale? haha.... :(

thanks.
 

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Hey Derek,

My understanding is that the ECM uses a PWM (pulse width modified) control signal to control the fan speed. I'm not sure if that's the signal on the violet wire that you tried to measure, but if it is then taking a DC voltage measurement won't be of any use. I wish I could offer some better info/advice.

Cheers,

Jeff
 

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Yeah, to properly measure the speed-controlled PWM fan signal you're going to need an oscilloscope. Otherwise, your voltmeter will simply be showing a sort-of-average that doesn't really tell you anything useful.
 

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Most likely the fan. Having developed these for a number of years, they are not without issues. It's rare that its the ECU or wiring. It's a pulse width modulated signal so you definitely need a scope to read it. Some fans can be tricked to running at full speed by pulling a line low, but I'm not familiar with this fan system in particular. I would recommend having it checked by a capable shop or getting your hands on a troubleshooting guide and a scope. I suspect you'll be needing a replacement fan in the end. I would start tracking one down if I were you. GL.
 

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First, if you have not already done so, confirm that you have 12VDC on the large red wire. It should always be there, even if ignition is off.

I do not know how you measured your 3.3V, were you measuring DC, AC (RMS)?

I just took a quick look at the violet wire on my 2005 V70R, and when there is a call for low fan speed, there is a 2.8V signal, 800usec,, 50% duty cycle.

As others have suggested, I do not suspect your ECU, and the potential you see seems appropriate. I do not think the amplitude of the signal is all that important. It is strictly pulse width/duty cycle. I don't believe the controller does anything with the signal other than amplify current and voltage. Same story with the HVAC fan, fuel pump controller, etc.
 

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Discussion Starter #7
well i bit the bullet and ordered a fan off ebay... it was listed as an 06 s60 fan but it looks exactly the same as my R fan (only 'R' fan listed cost $380, mine cost $225)... im hard pressed to believe its anything different. we will see soon enough as to whether it will fix my devilish car.

thanks for all the input.
 

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throwing parts at a car gets expensive fast. i would've like to have seen you spend some of that 225$ on having a capable mechanic properly diagnose it. don't assume that the fan you got on ebay is any good either. i've been down this road with people before..."but i just replaced that part, it has to be something else". is the ground is ok?
 

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Discussion Starter #11
throwing parts at a car gets expensive fast. i would've like to have seen you spend some of that 225$ on having a capable mechanic properly diagnose it. don't assume that the fan you got on ebay is any good either. i've been down this road with people before..."but i just replaced that part, it has to be something else". is the ground is ok?
trust me. im aware... problem is, they put the regulator in the same housing as the fan motor (on 06+)... fan was the most likely cause. i dont know a single technician that wouldnt agree with that.... i bought the fan under warranty at least, so i can get my money back if it turns out to be faulty.

ill be hunting down an oscilloscope tomorrow. the two points create a 12-14v supply, so the ground should be fine. ill be double checking them tomorrow to make sure i didnt some how blow a fuse during the installation (not too likely).

if anyone has a volvo wiring diagram (2006 s60r) see page 57.
 

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Discussion Starter #12
found my issue... i HAD 12v when my first fan blew out. i wired up a temp. fan that blew the fuse before i installed fan numero dos.... fan is back in action. thanks for the advice.
 
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