Auxiliary Fan Trouble

[olmsteade]

I own a 325i e30 that is having auxiliary fan problems. I did a little research and read that the most common thing is to have the resistor connected to the fan replaced as they burn out. I did this and the fan came to life as I turned on the A/C but after about 60 seconds the new resistor was extremely hot and the fan ceased to function. What could cause the fan to eat up resistors in this manor? Can the fan motor be drawing to much current or should I be looking for a short somewhere? Any help would be much appreciated as it is getting hot down here in AL and the car will need the fan soon.

[wcleafs]

what year is your 325?

I would have to look at the wiring diagram to see if the fuse is directly in the line or if it operates a relay which then turns on your fan.

If others have info they may help

If the thermo resistor is in line with the fan then it is possible for the fan to be drawing too much current and cause the resistor to heat up. Hot wires would be an indication of this too. Ideally the fuse should be your failsafe for this prob.

If you want to and have access to a multimeter you can put that in series with the aux fan to see what amount of current you are drawing.

If your unsure how to do it then let me know and will attempt to explain, rather simple and easy.

good luck

[olmsteade]

Originally posted by wcleafs@Mar 27 2005, 02:05 AM
what year is your 325?

I would have to look at the wiring diagram to see if the fuse is directly in the line or if it operates a relay which then turns on your fan.

If others have info they may help

If the thermo resistor is in line with the fan then it is possible for the fan to be drawing too much current and cause the resistor to heat up. Hot wires would be an indication of this too. Ideally the fuse should be your failsafe for this prob.

If you want to and have access to a multimeter you can put that in series with the aux fan to see what amount of current you are drawing.

If your unsure how to do it then let me know and will attempt to explain, rather simple and easy.

good luck

[snapback]319194[/snapback]

My 325i is an 89.

I do have a multimeter and I will try that. I am pretty green at all this though should I be paying attention to voltage, amps, or both?

If the motor is pulling too much current am I looking at replacing the whole assembly or can you simply purchase a new motor?

Also I have heard of some replacing the aux fans entirely for better units. Any idea of what those might be? I belieave I read of someone mounting an e36 aux fan in the e30.

[wcleafs]

Originally posted by olmsteade+Mar 27 2005, 11:58 AM--><div class='quotetop'>QUOTE(olmsteade @ Mar 27 2005, 11:58 AM)</div><div class='quotemain'><!--QuoteBegin-wcleafs@Mar 27 2005, 02:05 AM
what year is your 325?

I would have to look at the wiring diagram to see if the fuse is directly in the line or if it operates a relay which then turns on your fan.

If others have info they may help

If the thermo resistor is in line with the fan then it is possible for the fan to be drawing too much current and cause the resistor to heat up. Hot wires would be an indication of this too. Ideally the fuse should be your failsafe for this prob.

If you want to and have access to a multimeter you can put that in series with the aux fan to see what amount of current you are drawing.

If your unsure how to do it then let me know and will attempt to explain, rather simple and easy.

good luck

[snapback]319194[/snapback]

My 325i is an 89.

I do have a multimeter and I will try that. I am pretty green at all this though should I be paying attention to voltage, amps, or both?

If the motor is pulling too much current am I looking at replacing the whole assembly or can you simply purchase a new motor?

Also I have heard of some replacing the aux fans entirely for better units. Any idea of what those might be? I belieave I read of someone mounting an e36 aux fan in the e30.

[snapback]319442[/snapback]

[/b][/quote]


just checked the wiring diagram and the fan appears to be in parallel with the resistor, a little confusing on how it works but there are two fuses associated with it fuse number 3 is for the Aux fan blower resistor and fuse 18 for the aux fan.

You should be paying attention to amps to see the current draw. This may require a couple of jumpers to get it done. remove the red wire going to your fan and connect it to one lead of your multimeter. Connect the other lead of your multimeter to the connector on the fan housing and start the fan going, how ever you want to do that ie heat the car up or jump the resistor. With the multimeter on amps read the draw across the fan. I am not sure of the current draw of the fan but you may have to do some research to find that. check your local dealer and see if they can tell you.

as for replacement go the a wrecker and get on have them bench test it for you.
there are loads of after market fans for sale, some of the fellow bimmer drivers here may be able to direct you to a good site.

Hopefully that helps
cheers and good luck