2005 X5 radiator fan

[upallnight]

You can not just hookup a power source to the fan and expect it to run. The fan requires a pulse signal from the DME, that's the reason for the thin third wire that you see on the connector. Instead of using a resistor like in the past, the engineers at BMW decided to use a pulse signal to turn the fan on and vary the speed of the fan. Check the other two thick wires at the connector. One is ground and the other is 12V. If you don't have 12V then the 50amps fuse in the fuse box has blown. Only reason for the 50 amps fuse to blow is if the fan had a short.

[jcp240z]

Observe the fan as you start the car. The system spins the fan momentarily to check for proper operation.

[E53inLA]

I test the Aux fan by starting the motor and then pressing the Max AC button. The car is parked. The fan should turn on in 10-20 seconds.

[Quicksilver]

TerryZ91

Why not take it to the local indy you have a relationship with.
Can't take more than a few minutes for them to give it a check
and answer the question. This method is always better than guessing.

[TerryZ91]

Quicksilver, I would take it local indy but of course they would charge diagnostic fee, I figured I can instead spend that money on the repair.
Thank for clarifying that I can't start the fan by directly jumping the pin, I was on my way to buy a new fan. I wish I did have the npa/GT1 software so I won't have to go through so much trouble but unfortunately I don't a this moment.
I was able to get the fan started on AC by putting it on max AC and blower motor on full blast. I guess earlier I only turned the AC button on but did not increase the blower motor to full. It didn't turn on instantly when I turned the AC on but after 5 minutes of AC on full blast, it turned on. Also, when it came on, it was on momentarily than off then on and off (repeated the cycle) is that normal? I was also able to get the fan started by removing the connector on coolant temp sensor switch on the bottom hose coming out of the radiator. Of course, the check engine light came on and gave me a code for coolant temp sensor switch but the fan was on full blast at that moment. I think in future, for people who wants to check their fan can do this by just removing one connector and see if it turns on. I checked the female connector for the fan going to the motor, there is 12V reading and the (4) 50 amp fuses under the glove compartment are okay. However my fan does not turn on momentarily as indicated as indicated by JCP 240z to check for proper operation. I also read this somewhere that the fan is turned on for 20 seconds to check operation when you first start the car.
Let me see if I got this correct. So I'm guessing that fan is turned on by AC and temperature reading from coolant temp sensor switch. So my fan is okay from this diagnostic, right? I know the lower coolant hose coming out of the radiator was cool and top was hot. The fact that the bottom hose with the coolant temp sensor is cold, is not giving the signal to turn the fan on since the coolant is below certain temp and hasn't met the threshold to activate the fan. I know I read that the bottom coolant hose is usually cold and it's normal since the radiator is doing the job and cooling the coolant. I was thinking that maybe the thermostat is stuck closed but I don't think that is the case. Since my car has not overheated even once. The heater is hot. And of course the thermostat is not stuck open since the car warms up normally in 5 minutes. I was also leading toward the water pump impeller going bad but of course again due to lack of circulation the car will overheat and mine maintains the normal temperature even after 30 minutes of driving under load. Is it normal for my coolant hose to be cold then? I just want to confirm.

I got the expansion tank from the dealer today ($70), going to pick up coolant from the dealer ($25/gallon). The Zerex G05 is cheaper at $20 but in the end I think It's $50 from dealer v.s. $40 from Zerex. Of course this is for 100% concentration and I would mix with distilled water so it would be double the amount. I'm just going to replace the expansion tank, do proper drain and fill and see if here is still a leak and any problems are still there.

[upallnight]

Originally Posted by TerryZ91

Quicksilver, I would take it local indy but of course they would charge diagnostic fee, I figured I can instead spend that money on the repair.
Thank for clarifying that I can't start the fan by directly jumping the pin, I was on my way to buy a new fan. I wish I did have the npa/GT1 software so I won't have to go through so much trouble but unfortunately I don't a this moment.
I was able to get the fan started on AC by putting it on max AC and blower motor on full blast. I guess earlier I only turned the AC button on but did not increase the blower motor to full. It didn't turn on instantly when I turned the AC on but after 5 minutes of AC on full blast, it turned on. Also, when it came on, it was on momentarily than off then on and off (repeated the cycle) is that normal? I was also able to get the fan started by removing the connector on coolant temp sensor switch on the bottom hose coming out of the radiator. Of course, the check engine light came on and gave me a code for coolant temp sensor switch but the fan was on full blast at that moment. I think in future, for people who wants to check their fan can do this by just removing one connector and see if it turns on. I checked the female connector for the fan going to the motor, there is 12V reading and the (4) 50 amp fuses under the glove compartment are okay. However my fan does not turn on momentarily as indicated as indicated by JCP 240z to check for proper operation. I also read this somewhere that the fan is turned on for 20 seconds to check operation when you first start the car.
Let me see if I got this correct. So I'm guessing that fan is turned on by AC and temperature reading from coolant temp sensor switch. So my fan is okay from this diagnostic, right? I know the lower coolant hose coming out of the radiator was cool and top was hot. The fact that the bottom hose with the coolant temp sensor is cold, is not giving the signal to turn the fan on since the coolant is below certain temp and hasn't met the threshold to activate the fan. I know I read that the bottom coolant hose is usually cold and it's normal since the radiator is doing the job and cooling the coolant. I was thinking that maybe the thermostat is stuck closed but I don't think that is the case. Since my car has not overheated even once. The heater is hot. And of course the thermostat is not stuck open since the car warms up normally in 5 minutes. I was also leading toward the water pump impeller going bad but of course again due to lack of circulation the car will overheat and mine maintains the normal temperature even after 30 minutes of driving under load. Is it normal for my coolant hose to be cold then? I just want to confirm.

I got the expansion tank from the dealer today ($70), going to pick up coolant from the dealer ($25/gallon). The Zerex G05 is cheaper at $20 but in the end I think It's $50 from dealer v.s. $40 from Zerex. Of course this is for 100% concentration and I would mix with distilled water so it would be double the amount. I'm just going to replace the expansion tank, do proper drain and fill and see if here is still a leak and any problems are still there.

But the Indy can tell you if the fan is bad or not. Better to spend $100 for a diagnostic of the car then to spend $600 for a fan plus your labor to install a fan and then realise that it wasn't the fan.

[TerryZ91]

Thanks for your help everyone!! After $120, everything is in working order. I replaced the expansion tank ($70), radiator cap ($15), 2 gallon of zerex g-05 ($35). I drained the old coolant, filled up the new coolant and made sure to bleed it. The fan kicked in after 15 minutes and no more leaks!!

[dpgx5]

Hey, I have the software... how or where would I access this info?

If it's no trouble could you PM me.

Thank you!

[admranger]

Glad you figured it out.

For others who have this problem, the red wire to the fan is hot 100% of the time; key in, key out, etc. It's always 12v. Start there with a volt meter and see if you have 12v to ground. If not, there's a 50 amp fuse in the glove box (you test by checking for 12v to ground, not continuity, btw). If the fuse is ok and still no power, well then you get to find something I found! There's a 50A fusible link BEHIND the fusebox!

[chinoosoria]

Did you ever figure this out? Mine is doing the same thing but my ac doesn’t come out cold.