when ac on, fan noise
#1
07-09-2018 | 08:42 PM
when ac on, fan noise
i've got 03 mini cooper s with 90k miles. Recently when ac is on, every 10-15 seconds, fan makes noise like this video (not mine) below but it turns off after 5-7 seconds and back on. cold air blows fine but it really annoys me because it keeps on and off. i though it happens only at idle but even while car is running, i can hear that. is this normal or something wrong? Please advise.
Thanks
[YOUTUBE]
Thanks
[YOUTUBE]
#3
07-10-2018 | 07:15 AM
If what you have is the high-speed fan cutting in and out (which would be quite loud), I'd guess the circuit for the low-speed fan isn't working, so the high-speed cuts on and off repeatedly to make up for the absence of the much more quiet low-speed, which normally would be on continuously with the A/C running.
You can read through THIS behemoth thread for all the info on this common problem, which discusses wholesale fan failures (least common) bad relays (less common) and bad resistors (most common).
Once diagnosed, some folks replace the resistor with a more stout unit then relocate it to a different area of the engine... Me, I had this problem a few years back and just replaced the entire fan unit.
You can read through THIS behemoth thread for all the info on this common problem, which discusses wholesale fan failures (least common) bad relays (less common) and bad resistors (most common).
Once diagnosed, some folks replace the resistor with a more stout unit then relocate it to a different area of the engine... Me, I had this problem a few years back and just replaced the entire fan unit.
#5
07-13-2018 | 07:43 PM
Yup, that’s your high speed fan working to keep temps in check. Most likely your issue is a failed low-speed resistor (part of the fan assembly), which means it’s time for a new fan.
You can test the fan plug with a multimeter to confirm. Again, read the thread I alluded to in my earlier post for info on dealing with this common issue.
Aftermarket TYC replacement fans can be found on Amazon for around $70.
You can test the fan plug with a multimeter to confirm. Again, read the thread I alluded to in my earlier post for info on dealing with this common issue.
Aftermarket TYC replacement fans can be found on Amazon for around $70.
#6
07-13-2018 | 07:57 PM
Yup, that’s your high speed fan working to keep temps in check. Most likely your issue is a failed low-speed resistor (part of the fan assembly), which means it’s time for a new fan.
You can test the fan plug with a multimeter to confirm. Again, read the thread I alluded to in my earlier post for info on dealing with this common issue.
Aftermarket TYC replacement fans can be found on Amazon for around $70.
You can test the fan plug with a multimeter to confirm. Again, read the thread I alluded to in my earlier post for info on dealing with this common issue.
Aftermarket TYC replacement fans can be found on Amazon for around $70.
#7
07-14-2018 | 12:31 AM
Yup, that’s your high speed fan working to keep temps in check. Most likely your issue is a failed low-speed resistor (part of the fan assembly), which means it’s time for a new fan.
You can test the fan plug with a multimeter to confirm. Again, read the thread I alluded to in my earlier post for info on dealing with this common issue.
Aftermarket TYC replacement fans can be found on Amazon for around $70.
You can test the fan plug with a multimeter to confirm. Again, read the thread I alluded to in my earlier post for info on dealing with this common issue.
Aftermarket TYC replacement fans can be found on Amazon for around $70.
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#8
07-14-2018 | 05:01 AM
With fan functioning normally, when the coolant reaches 221°F (105°C), the low-speed fan comes on, then turns off when coolant comes down to 214°F (101°C).
If low-speed is not working, the fan will not come on until the coolant reaches 234°F (112°C), then it should revert to low-speed @ 227°F (108°C). Of course, if the low speed is not working, you get the temp spiking and high speed fan kicking on and off constantly, like you’re getting.
Also of note is if you turn the A/C on (even with engine cold), the low speed fan should come on. If it’s not, you have a problem with the resistor (most likely) or relay (less likely).
As to the fan, that’s the one I have. Does the listing confirm that it fits your car? Make sure your plug configuration matches up with the one shown on the product listing. Some earlier fans had a different plug with two separate connections.
Before you purchase the fan, you should get your hands on a multimeter and test yours to confirm that it is indeed your low speed resistor that has failed.
How to test the fan using a continuity meter or multimeter:
Disconnect fan plug from harness.
Put multimeter into continuity mode and touch the negative lead to the brown ground wire connection in the fan plug. Hold in place.
Touch positive lead to the thinner red wire (low speed fan) on the fan plug. If functioning properly, multimeter should beep. If no beep on low speed wire, the low speed resistor has failed.
Touch positive lead to the thicker red wire (high speed fan) on the fan plug. If functioning properly, multimeter should beep. If no beep on high speed wire, the entire fan has failed.
If you have continuity on both low and high speed, then the problem is not with the fan, and could be the low speed relay (on the fuse panel). This is less likely than it being the fan resistor.
#9
07-25-2018 | 12:41 PM
The problem with losing low speed fan operation is that your coolant is getting hotter than it would if the low speed was working.
With fan functioning normally, when the coolant reaches 221°F (105°C), the low-speed fan comes on, then turns off when coolant comes down to 214°F (101°C).
If low-speed is not working, the fan will not come on until the coolant reaches 234°F (112°C), then it should revert to low-speed @ 227°F (108°C). Of course, if the low speed is not working, you get the temp spiking and high speed fan kicking on and off constantly, like you’re getting.
Also of note is if you turn the A/C on (even with engine cold), the low speed fan should come on. If it’s not, you have a problem with the resistor (most likely) or relay (less likely).
As to the fan, that’s the one I have. Does the listing confirm that it fits your car? Make sure your plug configuration matches up with the one shown on the product listing. Some earlier fans had a different plug with two separate connections.
Before you purchase the fan, you should get your hands on a multimeter and test yours to confirm that it is indeed your low speed resistor that has failed.
How to test the fan using a continuity meter or multimeter:
Disconnect fan plug from harness.
Put multimeter into continuity mode and touch the negative lead to the brown ground wire connection in the fan plug. Hold in place.
Touch positive lead to the thinner red wire (low speed fan) on the fan plug. If functioning properly, multimeter should beep. If no beep on low speed wire, the low speed resistor has failed.
Touch positive lead to the thicker red wire (high speed fan) on the fan plug. If functioning properly, multimeter should beep. If no beep on high speed wire, the entire fan has failed.
If you have continuity on both low and high speed, then the problem is not with the fan, and could be the low speed relay (on the fuse panel). This is less likely than it being the fan resistor.
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