Coolant fan problems
06-07-2018, 08:06 AM
#1
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Coolant fan problems
i have an 2002 Audi A4 Quattro 1.8t I知 having problems with my coolant fans. They work for a couple seconds but only when I reset the battery. I知 thinking it my be a relay issue? Can somebody give me some input on this situation?? Please and Thank you!
06-08-2018, 05:18 AM
#2
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What do you mean by resetting the battery? Do they come on when you turn on the A/C? Does the car overheat?
The early A4's have a pretty simple fan system. I troubleshot mine down to the Fan Control Module which is essentially a relay with some logic in it.
The early A4's have a pretty simple fan system. I troubleshot mine down to the Fan Control Module which is essentially a relay with some logic in it.
06-08-2018, 09:05 AM
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What I mean by resetting the battery is i unhook it then hook it back up and the fan comes on for a second or so then doesn稚 ever come back on. Yes it over heats if I知 not on the highway, I have only driven it a couple times since the fans aren稚 working. How can I go about testing the module?
06-08-2018, 12:21 PM
#4
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The module is mounted just to the right (driver's side) of the hood latch at the top of the fan assembly (see the link for a picture of the FCM). I troubleshot mine the following way:
1) I will skip any checking of fuses since it does monetarily run...
2) Trace the connector to the outside of the car and disconnect it. It is near the coolant reservoir. With the A/C on (Econ light off), start the car. Test across the 2 larger connections and the 2 smaller connections with volt meter. I used to have a picture of it, but can't find it. I think the there are 4 connections, the two larger are the power wires. Also, look for the brown wire which is a power wire. Try several combinations, but if you get a constant 12ish volts, your are good.
3) The only way I could figure out how to measure the voltage on the other side of the FCM is to peel back the insulation on the wires as there are no connectors on that side. Pick either pair of wires (2 go to each fan). Start the car and measure the voltage on the 2 wires. Make sure the fans aren't turning!!! I did not get any voltage.
4) My final step was to shut the car off and directly jumper the fan to the battery. In my case, it spun up immediately.
Note you will have to butt splice the new FCM to the fan assembly. If you have no experience doing that, just make sure and buy the right tools and take your time. First time I have done it and took me a few tries to get it to my satisfaction.
https://www.ecstuning.com/Search/Sit...ontrol_module/
1) I will skip any checking of fuses since it does monetarily run...
2) Trace the connector to the outside of the car and disconnect it. It is near the coolant reservoir. With the A/C on (Econ light off), start the car. Test across the 2 larger connections and the 2 smaller connections with volt meter. I used to have a picture of it, but can't find it. I think the there are 4 connections, the two larger are the power wires. Also, look for the brown wire which is a power wire. Try several combinations, but if you get a constant 12ish volts, your are good.
3) The only way I could figure out how to measure the voltage on the other side of the FCM is to peel back the insulation on the wires as there are no connectors on that side. Pick either pair of wires (2 go to each fan). Start the car and measure the voltage on the 2 wires. Make sure the fans aren't turning!!! I did not get any voltage.
4) My final step was to shut the car off and directly jumper the fan to the battery. In my case, it spun up immediately.
Note you will have to butt splice the new FCM to the fan assembly. If you have no experience doing that, just make sure and buy the right tools and take your time. First time I have done it and took me a few tries to get it to my satisfaction.
https://www.ecstuning.com/Search/Sit...ontrol_module/
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