BMW-Driver.net Forums banner
Cancel
Create thread New Garage Forums

E46 318ci cooling fan always on

Jump to Latest
8.6K views 8 replies 3 participants last post by  BavarianCare  
B
#1 ·
Picked up an e46 coupe recently and I'm having a problem with the cooling fan that sits between the engine and the radiator. I start the car and after about 10-15 seconds the fan come on and goes upto full blast. It turns off again when I switch off the car. So far I've replaced the radiator outlet temp sensor and the temp sensor on the thermostat housing in front of the engine. They haven't helped the fan issue. When I got it plugged in it was throwing up a code for temp sensor and something about the fan, the temp sensor code is now gone but the fan code is staying. I don't have any engine management light on. As far as we can see the fan doesn't seem to be wired in to remain on all the time either. Also, the air con radiator is missing from the car, a stupid oversight when I was viewing the car but there's always something I miss!!
So does the air con rad not being there have anything to do with the cooling fan coming on? Does the fan unit itself need replacing or is there something else I should try before paying out for a new fan?
Cheers
 
B
#2 ·
Ok so I had a good second hand fan fitted and it did the same thing. I have it down to either it being wired in like that or something to do with the air con.

@edber cheers for that. I've had an air con rad fitted also now. I haven't yet gassed and pressurised the system though. I'll try that as soon as possible hopefully it will sort it. Also my ambient air temp sensor is reading -40 all the time so that's goosed but I have the part here. Does that sensor have anything to do with the fan?
 
B
#4 · (Edited)
Ok just to clarify the ambient temp sensor definitely has an effect on the operation of electric fan?

I checked for the sensor on top of the drying container and it seems to be there from what I can see. It is not plugged in though. I must see if I can find the connector for it. I hope it's still there and wasn't cut out for some reason
 
B
#6 ·
The only fault code it's showing is '108 - Cooling fan circuit'

I've googled this code and can't find anything. I've found the 3 wires for the air con pressure sensor but there's no connector so I must try get one from a breakers yard and see if that makes any difference.

From looking on e46fanatics I've found that the following affect the cooling fan:
-coolant temp sensor
-calculated catalyst temp
-vehicle speed
-battery voltage
-air conditioning pressure

That is lifted straight from a Siemens technical guide on the engine electronics. So I'm going to at least try and get some pressure in the system and see if it works. Worth a shot anyway and it'll be another thing off the list even if it doesn't help the fan issue. Thing is now I can't for the life of me find the ambient temp sensor wires. I know they're blue/red and blue/brown and they should be in front of the passenger wheel somewhere but I can't find them at all. I must do some more rooting tomorrow.
 
B
#8 ·
To finish this one if anybody experiences the same problem, I've it sorted as of today. I wired a connector onto the 3 wires for the pressure sensor on the air con, plugged it in and no more constant running fan. I also wired up a new ambient temp sensor so thats reading correctly again also. The 2 connectors cost me all of €2 from a breakers so a cheap simple fix in the end. Cheers to edber for the info
 
BMW-Driver.net Forums
posts
656K
members
16K
Since
2003
A forum community dedicated to all BMW owners and enthusiasts. Come join the discussion about performance, modifications, tuning, specs, classifieds, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
Introduce yourself BMW common problems and issues General Motoring Discussion