Aux fan.....

[Jake335i]

I recently bought an 01 X5 4.4. I was tracking down service records and found one that claimed the aux fan and sensor needed to be replaced...

How do I test if it is still faulty, or has been replaced?

(What triggers the fan to kick in...only extreme temps, towing, steep inclines, etc...anyway I can test it ow that it is -10 outside...??)

[4.8isX5]

Yes, if you have INPA, its in there. I dont recall exactly which menu as its been a while however I know ive messed with the setting and it lets you turn it on and off through the software, should be in the same menu where you can toggle the fuel pump relay etc.

[g300d]

The aux fan has 3 wires, an always live positive, a ground, and a PWM signal wire from the DME.

The DME controls the fan taking input from the coolant temp sensor in the lower rad hose and the AC system pressure switch IIRC.

There is a diagram floating around here of the system as posted by Qsilver7 if you can find it.

A quick test to see if the fan is working is to put the AC on MAX. The fan should turn on.

Also, the fan self tests on cold starts, it should turn itself on for a few seconds IIRC.

[Jake335i]

Thanks guys.

4.8isx5 not sure exactly what INPA is....I order a Scanner 1.4, if that is what you are referring too. (I haven't received it yet)

G300d- Will that test still work if the temp outside is current -5 Fahrenheit or is there an ambient temp switch that will interfere with the test??

[g300d]

That I am not sure. The cold start test *should* still work.

What is making you want to check aux fan function btw?

[Jake335i]

Originally Posted by g300d

That I am not sure. The cold start test *should* still work.

What is making you want to check aux fan function btw?

Just bought the vehicle....I contacted a company for which I found a receipt in the car out of CO. They were nice enough to supply me with the service history that they had performed, also a list of items they had quoted for the PO.

Among the list of quotes items:
Torn CV boot (I verified still torn and ordered a replacement)
Seep belt (which also still appears to be in poor condition)
Control arm bushings (still bad)
Aux fan and fan switch

So, I am just trying to verify if any of the POs repaired the fan, before I order the parts.

If it is faulty, is there any downside to having it not working during these cold winter months?? I am guessing it kicks in if engine temps get to high, but considering the temps we are having now, I don't see it as an issue....??

[g300d]

At those temps I doubt it will be a problem. I notice a lot of people with fan problems that post here never notice it till the warm months, if at all. Just watch your temp gauge.

You can monitor the actual coolant temp on your cluster while driving (OBC test 7) to be doubly sure.

[Qsilver7]

[Jake335i]

I drove for a "spirited" drive today (ambient temps were 5 degrees) got the temps to 103C (217F) that seems hot to me, but I guess no need to worry til summer as it looks like, based on Quicksilvers post, fan doesn't kick on til 120c, which is 248f...that seems way too hot for me....but I don't know much.

[g300d]

103c is still in the usual operating range for the V8. Nothing to worry about there.