X5 AC strange behavior

[mysweetx5]

No slick!
I do not fully agreed with you on thiseconomic way
Coz everyone is looking a cheapest way out, instead of
being charged with the higher stealer price for every single thing.
And if I could put down: $22,000+in cash to get my X5 when I first
bought it 6yrs ago, this $500 machine is not a big issue to own.

By the way I would love to have heavy duty tools like that to work
at home, but it just where I live I do not have enough space to built
my own garage. Otherwise I've been doing alot on cars for the past
6yrs without going to any stealers. And I have to thank all of you guys
in this forum that made it possible and shared pictures for everyone.

The last heavy job I completed on this car was: replacing transm. fluid.
2months ago, it still running great as usual.

[TerminatorX5]

The Aux fan is designed to run at various speeds to help with the heat exchange. The older cars used a resistor pack, similar to the FSR on the inside fan blower, the newer cars (i think, including yours), are using a Pulsed modulation, when the IHKA module feeds so much electricity to the fan, and it spins at variable speed.

The fan, being placed in front of the car, is known to collect bugs, leaves and other crap and eventually, that crap craps out the motor. It has been documented on other boards, that some folks had removed the fan and cleaned the creaveces in the electric motor area and thus revived the fan.

BMW moved the fan on newer cars behind the radiator thus preventing that particular problem of the fan getting bombarded with bugs...

How is your AC when you are moving? Say, you are on a freeway, and moving 50-60 MPH, is the AC functioning as designed?

[TerminatorX5]

directly from the HORSE's mouth:

Vehicles with M62TU, S62 and M73 engines feature a viscous fan as well as an electric fan. The electric fan cuts in when the cooling capacity of the viscous fan is no longer sufficient.
The electric fan is activated by means of a power output stage directly on the fan motor. The motor control unit activates this power output stage by means of a square-wave signal with duty factors (variable pulse width) between 10 % and 90 % thus controlling the various speeds of the electric fan. Pulse duty factors less than 5 % and greater than 95 % do not trigger activation but rather they are used for fault detection purposes. The power output stage features its own positive and ground supply.
The fan speed is influenced by the coolant temperature at the radiator outlet and the pressure in the air conditioning system. The fan speed is reduced as the vehicle speed increases.
If a fault occurs during operation a corresponding fault code will be stored in the fault code memory of the DME control unit.
For the purpose of checking operation and troubleshooting, the diagnostic program offers the option of activating the electric fan directly via the DIS tester/MoDiC.

[stwjazz7]

I've been away for awhile. It was nice to login and find a thread dealing with my issue and to see some soud advice being givin. My X started blowing warm air when stationary for awhile. Once moving it gets as cold as ever. I don't have to be on the highway, just moving along. The compressor click when engaging is more loud than usual and the engine bogs down more than usual when this happens. So I will check the r134 pressure/level, the aux fan and relay first. Thanks for the advice. 2001 X5 3.0i.

[mysweetx5]

Welcome back diazz!
As you described, we have similar issue on our X5,
once I hit the road independ how hot it is outside, meaning
if the temperature is around: 94 to 100's, it kind of hard to keep-up
with this highest heat outhere. In addition, my Aux fan has not been
working at all.
Thats when I searched the forum on A/C problem not blowing cold enough
on traffic, but came up to this auxiliary fan that also apart on the colder
air inside the cabine. And when I watched closely for hours, found out this fan has never been spinning when A/C kicks in. I can notice that my compressor is running, spinning time to time but not my Aux fan.

[TerminatorX5]

I forgot if anyone has asked or not: can the aux fan be span by hand? or, it is stuck?

[SlickGT1]

Originally Posted by TerminatorX5

directly from the HORSE's mouth:

The fan speed is influenced by the coolant temperature at the radiator outlet and the pressure in the air conditioning system. .

This means your shit won't spin when freon is low. How long will it take for people to go and get their AC checked by a pro? I'm just curious which one is going to replace the fan first.

[bastereo]

Slick, nope just the shotgun approach.

OP, that "relay" you asked about and posted a picture of that is the AUC sensor, like the name says- sensor. Search and find out what it is if you don't know. But if would be listed as a relay if it were a relay.

You could, if you had access to a GT1 or anything that does BMW specific codes, see if there are any stored trouble codes for the fan.
And before anyone suggests it, Autozone or any cheep code reader isn't going to help.

[SlickGT1]

I agree. I am aging going from easy to hard method. There were two members recently that filled AC. Fan went from dead stop to spinning like a raped ape as pressure was built up. Relay testin, you need to know what you are doing. The fan is also a pulse signal fan, so to make it spin, you would need to supply power, ground, and a pulse ground.

Without really seing the OPs car, you cant tell. Without GT1, it is that much harder. $50 AC check is really not a lot of money.

[TiAgX5]

Originally Posted by SlickGT1

I agree. I am aging going from easy to hard method. There were two members recently that filled AC. Fan went from dead stop to spinning like a raped ape as pressure was built up. Relay testin, you need to know what you are doing. The fan is also a pulse signal fan, so to make it spin, you would need to supply power, ground, and a pulse ground.

Without really seing the OPs car, you cant tell. Without GT1, it is that much harder. $50 AC check is really not a lot of money.

Yeah, that was me that posted the direct correlation between low pressure side reading and fan speed. I think I said date raped ape. At 50psi on a 100 deg F day the fan sounded like a turboprop cleared for takeoff!