air cond question

[bigwave2255]

ok called in on the a/c repair guy and he says i have to take it to an auto electrician first as he cant diagnosis a faulty fan.he said that if when running the a/c is cold then he doesnt believe its low on gas ( and it does)

seems i may have two faults
1/ that, as others have experienced the a/c is slow comming on, often taking up to 10 minutes, and especially if the car has been sitting for a couple of days or its been sittin in the heat
2/ the cooling fan in front of the radiator is not working, causeing the a/c to loose efficiency when the car is stationary.
ive checked and there is 12 volts to the fan however i cant tell if the fan motor is dead or its not getting pulsed to switch on so.........

i had a look on ebay and came across this (251186015362) is this what i need to access my cars software?? using this can i turn on the fan or at least determine if its ok??

and is this what people use to reset and turn on/off different functions

all help is greatly appreciated

ive stayed away from messing with my cars functionalities and reprogramming although have researched and followed many threads on the topic.

i think its time i bit the bullet and got into it

oh my car is a 2005 x5 3.0d sport

[SlickGT1]

Can you post a link? Thanks.

[Yarno]

That unit from eBay is like the car soft one I have. All it can do is tell you there is a fault with the fan and a small amount of set coding.
This is more like what you need
http://bit.ly/QAEvU0
BMW GT1 DIS v57 SSS V41 V41 FIT ALL COMPUTER OPS TIS
Or look up icom BMW on eBay.

[bigwave2255]

kool thanks

just got my car back from the mechanic 150,000 k service and oil service plus they couldn't conclusively diagnose the fan so they took it to auto electrician $700 geeeesss

anyway apparently the fan controller on the fan motor is dead, and BMW want wait for it

$1400.00 for a replacement PLUS labour to fit, thay have to be joking

looks like i will be searching out a fan and doing the job myself.

somebody recently posted a how to so thanks guys its going to come in many thanks

update, just ordered a fan locally from a guy who imports from Germany just under $500, so just a little more that a third of what BMW want

[Yarno]

Yeah I got quoted $1400 as well. Imported one from the US, the fan motor is the same at the petrol one it's just the shroud that is different.
Hope that fixes yours, it didn't fix mine...

[SlickGT1]

Originally Posted by bigwave2255

ok called in on the a/c repair guy and he says i have to take it to an auto electrician first as he cant diagnosis a faulty fan.he said that if when running the a/c is cold then he doesnt believe its low on gas ( and it does)

seems i may have two faults
1/ that, as others have experienced the a/c is slow comming on, often taking up to 10 minutes, and especially if the car has been sitting for a couple of days or its been sittin in the heat
2/ the cooling fan in front of the radiator is not working, causeing the a/c to loose efficiency when the car is stationary.
ive checked and there is 12 volts to the fan however i cant tell if the fan motor is dead or its not getting pulsed to switch on so.........

i had a look on ebay and came across this (251186015362) is this what i need to access my cars software?? using this can i turn on the fan or at least determine if its ok??

and is this what people use to reset and turn on/off different functions

all help is greatly appreciated

ive stayed away from messing with my cars functionalities and reprogramming although have researched and followed many threads on the topic.

i think its time i bit the bullet and got into it

oh my car is a 2005 x5 3.0d sport

Wait so did he actually try and evacuate the system and refill it?

[bigwave2255]

no he wouldn't touch the gas, he said that if the thing blows cold when running then in his opinion the gas level was ok, he sent me off to sort out the fan first.

so i had my mechanic test the fan ( something i learnt here , thanks) and the software said it was inconclusive, so the mechanic sent it to an auto electrician, who tested the fan and concluded that the controller is dead.

so ive ordered a new fan, and will fit it myself ( again thanks to this site) and see what happens.

i saw on Bimmerfest someone claimed that if the pusher fan was faulty then that can also cause the a/c to be slow starting, i assume that the a/c controller may pulse the fan, and if it doesn't get the response it expects then doesn't allow the a/c to kick in till other parameters are met, just guessing here as i simply don't know.

however once the fan is replaced then i can assess the thing further.

[Yarno]

Checked the signal coming from the black wire on the fan with an oscilloscope and found it very eratic. It is showing a square wave PWM signal but it was between 3-5volts while the fan was turning and when it was stoped it was all over the place .44V to 2V.

I also have another spare new fan here that I plugged in and it did the same thing, stops after about 10secs.

Does anybody know where the signal comes from? or have and schematics.

[SlickGT1]

I am pretty sure it is directly related to the pressure switch coming from the AC system. Not sure where it comes from, but you are not the first to report the same findings. Please go to another AC shop and get them to evacuate and refill the system. It should not cost much, but it will, at least make sure that is not the issue.

[Turbo_Bimmer]

Originally Posted by Yarno

Checked the signal coming from the black wire on the fan with an oscilloscope and found it very eratic. It is showing a square wave PWM signal but it was between 3-5volts while the fan was turning and when it was stoped it was all over the place .44V to 2V.

I also have another spare new fan here that I plugged in and it did the same thing, stops after about 10secs.

Does anybody know where the signal comes from? or have and schematics.

That voltage level seems ok. There is a power transistor in the fan box that is driven by this low voltage signal. There should be also a 12V and GND wire (bigger wires) that have a potential of 12V between them while the fan is running.
Check to see if there is still 12V between the 2 big wires when the fan stops. If not, either the ECU decided to turn off the fan, or there is a bad contact somewhere. If there is still 12V but no PWM signal, I would check the signal wire to make sure everything is normal.