Coolant Fan not turning on

jeffrie · 10-10-2011, 10:21 AM

Annoying issue,
Sit in traffic it starts to heat up and have to crank the heater to stop it from over heating.

What I'v done was change the sending unit off the rad, no dice and manualy jumped the fan with a 12 volt power source, That worked so the fan is still good.

Was thinking the fuse but look at fuse box and it says # 48 and 40amp with a astrix beside it.
Astrix means that the fuse is located under the steering colum.

I looked long and hard under the steering wheel right till it goes through into the firewall and I can't find it.

Any one have any experience on this to share with me?

M44 1.9l 4 pot FYI

Ceeker · 10-10-2011, 11:00 AM

it might be the fuse, Might need to be replaced. the only reason a fuse blows is due to system overload. So if your fan works properly this shouldn't have happened. that means there is resistance coming from the fan, bearing, making noise? did you notice whether the fan took longer to spool up?

this is a good article but doesn't indicate where your 30amp fuse is located. in the 2nd link I see it does say below steering wheel. 2nd thought. did you also check fuse #16? it's a 5amp. most likely you blew that one. that is located in the fuse box. since yours is a 4cyl #16 and #48 are the two.
I would think the weaker of the two blew.

go here: http://www.dvatp.com/bmw/diy/aux_fan/

fuse panel layout: http://www.bmwe36blog.com/image-view...-box-layout-04

I think you'll find this informative.

GL :-)

jeffrie · 10-10-2011, 12:24 PM

Thanks Ceeker, info helped but it's mainly just purly for the BMW's with 2 fans.
1 electric Pusher and a belt driven Puller fan.
M44's only have one 2 speed electric puller fan located where the normal belt diven fan is on most E36's, no aux fan up in front of the AC condencer and rad.

Oddly the pic in 2nd link is different then my panel.
Mine doesn't have # 16 & # 48 just # 48 alone and is 40 amp instead of 30, but I do have a 16 for AC so checked it was good, replaced it anyway and still doesn't turn on.

I did jump from the sender as described to test the relays in your links.
At first no problem High speed turned on instantly, no abnormal noise, spools up nice and fast and obviously the fuse (where ever it may be) isn't blown as it is working through the high speed relay.
Try jumping the low speed and Bingo, nothing happens.

Looks like my low speed relay is no good, now need to find out where that relay is hidden.

Little confused though as you'd think once it was hot enough the high speed fan would kick on regardless even with the low speed not working.

Ceeker · 10-10-2011, 12:52 PM

Quote:

Originally Posted by jeffrie

Thanks Ceeker, info helped but it's mainly just purly for the BMW's with 2 fans.
1 electric Pusher and a belt driven Puller fan.
M44's only have one 2 speed electric puller fan located where the normal belt diven fan is on most E36's, no aux fan up in front of the AC condencer and rad.

Oddly the pic in 2nd link is different then my panel.
Mine doesn't have # 16 & # 48 just # 48 alone and is 40 amp instead of 30, but I do have a 16 for AC so checked it was good, replaced it anyway and still doesn't turn on.

I did jump from the sender as described to test the relays in your links.
At first no problem High speed turned on instantly, no abnormal noise, spools up nice and fast and obviously the fuse (where ever it may be) isn't blown as it is working through the high speed relay.
Try jumping the low speed and Bingo, nothing happens.

Looks like my low speed relay is no good, now need to find out where that relay is hidden.

Little confused though as you'd think once it was hot enough the high speed fan would kick on regardless even with the low speed not working.

I don't know enough about the e36 integrated fans but do know they have integrated resistor inside.

I would just replace the low speed relay - test it and see what happens. if it works great!

Last resort?: you may need a new pusher fan - maybe internal resistor is on its way out?

jeffrie · 10-11-2011, 10:52 AM

Just an update.
Found the relays and high speed and low speed are two seperate relays but are the exact same, tried swapping them but could only get the high speed working via jumping the connection.
Must have an electrical issue somewhere in the circuit for low speed.

Will have to trace it later... for now I just ran a toggle switch to my high speed signal wire out from the temp sensor that I can just manualy turn on once I hit traffic bypassing the way it normaly works... likly will be the permanent fix lol.

Thanks for the help Creeker in trouble shooting this.