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Discussion Starter · #1 ·
well i did cooling system overhaul and replaced lot of parts but some how electric cooling fan dont come on when engine is normal or high temp? how can i tell its not burned up or how can i test this problem? i reall dont want to spend over 300 bucks for new fan. :cry:
 

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Your thermoswitch is either bad or not functioning....
 

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Unplug it and give it direct 12 volts. The fan should run. This will tell you if the motor works.
 

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Discussion Starter · #4 ·
ok what color wires do i hook up where to test this? and i checked 50amp fues looked alright but had brown tint on both teeth.? and some one told me When AC is on electric cooling fan should always come on is this true???
 

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No, only comes on when the coolant is too hot. If the belt/viscous clutch fan is moving enough air (assuming your car has auto transmission), electric fan won't run. See your "what's this wire for" thread for an explanation of the coolant temp sensor found in the radiator.
 

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Discussion Starter · #6 ·
No, only comes on when the coolant is too hot. If the belt/viscous clutch fan is moving enough air (assuming your car has auto transmission), electric fan won't run. See your "what's this wire for" thread for an explanation of the coolant temp sensor found in the radiator.
well i did check coolant temp sensor it is pluged in (lower radiator hose) this little wire is on driver side by head light and dumper. and i do know electric cooling fan comes on when it gets hot. i did run the car almost to the red line on engine temp never came on. so i shut the car down to cool the engine because i didnt want to blow head gasket.
 

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Discussion Starter · #9 ·
haha sorry i am new guy to bimmerfest lol well i by passed heat sensor to test electric fan made sure it worked and it was also 2 speed fan one at idle and one at full speed. than i check the lower radiator temp sensor like u told me to after engine was at 200f it was cold Thermostat did not work so the heat sensor was reading cold because Thermostat never opened up so i have to order new Thermostat. so that was why fan never came on and didnt have good flow to radiator to get cooled and that is why i had heat problems. but i did learn lot from u all. thanks again
 

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Hey, didn't you say in your other thread that you had gotten this car on the cheap cause of a blown head gasket and that a cooling system overhaul had been performed as part of getting it back to usable condition?

IIRC, the thermostat is one of the basic items to be changed in such an overhaul, so aren't you paying twice for the part?
 

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Discussion Starter · #11 ·
Well this car was great deal because of the price and it came with tools and most of new cooling system parts still in boxes but it came with 2 thermostat open box so i just put one on when i was putting it back together. was not sure witch one was the new one. so ya lot a cooling system part was replace just Thermostat was open box and when i bought the car lot of the parts were just sitting in the trunk and found 2 Thermostat so got a try both before i buy another one and seller move out of state so i cant even return the new Thermostat for new one.
 

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Hi I'm new here I'm having a problem with my 2008 bmw 335i. My a/c will not work. It only works at night or morning usually when it's cool outside. When it's hot it only blows hot air. I took it to the mechanic and he said it was the compressor that was bad. Can some one point me in the right direction before I spend over a 1k on just the compressor
 

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PLEASE READ THIS (I GOT MY ISSUE RESOLVED WITH THE ELECTRIC FAN, maybe this can help someone in the future)

i've had the fan stop working on me during traffic, car overheated, no engine codes, no CEL, when i plugged in the BMW software, it gave a code for Fan Activation. I tried activating the fan but it didnt work, so i bought a new electric fan, when i installed it, i tested it using the BMW software, it worked fine, and continued so for a week, til overheat again. i plugged the car again to the computer, tried to activate the fan using the software, didnt work... went to the parts store, got another fan under warranty, it worked for a couple of days, and died again. being sure that it's not the fan anymore, i doubted the signal wire running from the car wiring harness to the fan. it is really hard to check the signal on that, the strange and funny thing is that it was showing some signs of life when i plug in the multimeter to the signal wire (green and black, thin wire running from the car harness to the fan connector) so i assumed that it was working fine... never assume something with BMWs, that's what i learned.
the next day, car overheated again while being stuck in traffic, i had to pull over and just wait for traffic to ease off so i can drive the car at speeds where the temperature is more steady til i get it home... i got fed up and checked the diagram, traced the Signal Wire (the Green and Black wire) to the (ECM) Engine Control Module connector and found it to be Pin #4 on the circuit diagram for the electric fan (look up "electric fan E46 Circuit Diagram", on the web, you will find it), unplugged the connector at the fan, and the other end at the ECM, checked continuity of that wire, only to find a 1K Ohm resistance on that line, which, after discussing with an electrical engineer friend, found it to be suspiciously too high) i spliced the wire from the engine control module (ECM) to the electric fan connector, it worked, i've been driving the car now for few days with no issues, and the fan does come on much more than it used to before... also, note this: i had tested my old fan (i didnt throw it out), and it turned out that there was nothing wrong with the original BMW electric fan, it fired right up...

I really hope that this can help someone in the future...
by the way: the AC used to cut off when i'm at a stop in traffic, i thought i had a problem with my AC, but it turned out that once i fixed the fan issue, the AC problem disappeared
also note: when i say the car overheats, i was suspecting something wrong when the AC was working normally and it shuts off at stops... so i didnt let the heat reach more than 3/4 at the heat gauge, i always turned it off before it went into the Red Zone.
 

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I have a similar problem and cannot find my specifics after doing a lot of research and forum reading, so I hope someone here could help me. I noticed my cooling fan stopped working and would only come on when I had the AC on. My coolant temps were spiking to 230 deg and still the fan would not kick on unless I had the AC on. Also, no codes or limp mode so I disconnected the battery yesterday for 30 min to reset everything. When I reconnected it, the fan was working properly, coming on low mode when the engine is hot and high mode with the AC. I thought the problem was fixed until this morning where its doing the same thing again and I cannot figure out why. Any help would be greatly appreciated before I take it to the dealer.

Thanks!!!
 

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I did, but I'm not sure if that is the culprit since my fan works with the AC on, just not when the AC is off. It's still under warranty but I wanted to check all possible causes and see if this is a common event which justifies taking it to the dealer, or if its a "one off" thing.

Thanks for your help. :)
 

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Mine did that too, I felt that it wasn't working right, but with time, it just completely stopped... it was a slow deterioration of the signal (it seems)...
When the resistance increases in the wire, it appears to still deliver a signal but not for all 4 speeds of the fan...
 

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PLEASE READ THIS (I GOT MY ISSUE RESOLVED WITH THE ELECTRIC FAN, maybe this can help someone in the future)

i've had the fan stop working on me during traffic, car overheated, no engine codes, no CEL, when i plugged in the BMW software, it gave a code for Fan Activation. I tried activating the fan but it didnt work, so i bought a new electric fan, when i installed it, i tested it using the BMW software, it worked fine, and continued so for a week, til overheat again. i plugged the car again to the computer, tried to activate the fan using the software, didnt work... went to the parts store, got another fan under warranty, it worked for a couple of days, and died again. being sure that it's not the fan anymore, i doubted the signal wire running from the car wiring harness to the fan. it is really hard to check the signal on that, the strange and funny thing is that it was showing some signs of life when i plug in the multimeter to the signal wire (green and black, thin wire running from the car harness to the fan connector) so i assumed that it was working fine... never assume something with BMWs, that's what i learned.
the next day, car overheated again while being stuck in traffic, i had to pull over and just wait for traffic to ease off so i can drive the car at speeds where the temperature is more steady til i get it home... i got fed up and checked the diagram, traced the Signal Wire (the Green and Black wire) to the (ECM) Engine Control Module connector and found it to be Pin #4 on the circuit diagram for the electric fan (look up "electric fan E46 Circuit Diagram", on the web, you will find it), unplugged the connector at the fan, and the other end at the ECM, checked continuity of that wire, only to find a 1K Ohm resistance on that line, which, after discussing with an electrical engineer friend, found it to be suspiciously too high) i spliced the wire from the engine control module (ECM) to the electric fan connector, it worked, i've been driving the car now for few days with no issues, and the fan does come on much more than it used to before... also, note this: i had tested my old fan (i didnt throw it out), and it turned out that there was nothing wrong with the original BMW electric fan, it fired right up...

I really hope that this can help someone in the future...
by the way: the AC used to cut off when i'm at a stop in traffic, i thought i had a problem with my AC, but it turned out that once i fixed the fan issue, the AC problem disappeared
also note: when i say the car overheats, i was suspecting something wrong when the AC was working normally and it shuts off at stops... so i didnt let the heat reach more than 3/4 at the heat gauge, i always turned it off before it went into the Red Zone.
Hey do u have a video of this im kinda lost on this i have this issue

hello, i know is is old but searching on the web i find this and is close to what is happening to me, i have a F30 in the diagnostic shows “1A2004 fan control cable disruption”, the car is overheating, i change fan and still the same, i notice that the fan acts like is goin to start then stop, i was looking at the connection to the fan i notice that the connector has 3 cable 2 big + and ~ and there is a 3 cable small gauge im guessing thats the ecu signal, how do i test that cable and is that cable + or - also how do i test the fan directly when i apply current to the fan + and - dont do anything so i guess that small teeth needs also to be given power, but is is + or -

also it happends the same the car when at idle ac stoos cooling but im sure is cos the fan problem i think i have this problem also but im a little confuse on how to fix it
 
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