Radiator Fan no low speed

[handsomejackuk]

Hi,

trying to prove my radiator fan is working and by shorting out two terminal on the radiator fan switch i get high speed but cant get low speed fan working, any ideas, have swapped relays over high speed and low speed for other ones and still not working...

also is it correct that the radiator fan should come on low speed when air condition is active ?...
as mine does not .. beginning to suspect a blown low speed resistor on the radiator fan...

car is 1998 m44 engine electric fan with air con...

 

[Brian H]

There is a big electrical plug on the fan, split this and test at that point, you should have 3 wires in the plug, a ground and two switch wires, one for low speed and one for high speed. Once you know the fan will s working you can work from there.

 

[t-tony]

A "Power Probe" is very good for this type of problem tracing.

http://www.ebay.co.uk/itm/Sealey-Au...538323?hash=item5b18a5ba93:g:uTYAAOSw9r1V8FjM

Tony.

 

[handsomejackuk]

going to probe my relay sockets this morning to see if i can activate the low speed fan ... i always use a current limiting bulb when i test these sort of things, so going to make up a lead with some crimps and test terminals to make the job a bit easier... i dont really know if the airconditionning is working properly.. not too botheres about that just want to make suer the fan comes on correctly

 

[Ianmc]

I think there is a plug known as a "hedgehog" that often is the source of such problems.

 

[Dino D]

I've had this issue on a 2.8 (the aircon fan or auxilary fan).
It never ever worked on low speed.
It only worked when the AC was on (at full speed, not low speed).
It was supposed to kick it at low speed when sat in traffic without a AC on.

Turns out a number of 2.8's were wired incorrectly by the factory...
Here is a thread where a couple of us dealt with this issue @deni2s is also one here:
https://www.bimmerforums.com/forum/showthread.php?2207733-Z3-2-8-electric-fan-failure

It sounds like you have the same issue we had on the 2.8.

It's now fixed by correcting the pins and my car runs only the electric fan (no viscous) and it kicks in at low speed as needed and I've only ever heard high speed being used whe AC is on.

 

[deni2s]

The brown wire must be in the middle. If it's not, you need to rearrange ALL wires so that brown is in the middle.

 

[t-tony]

going to probe my relay sockets this morning to see if i can activate the low speed fan ... i always use a current limiting bulb when i test these sort of things, so going to make up a lead with some crimps and test terminals to make the job a bit easier... i dont really know if the airconditionning is working properly.. not too botheres about that just want to make suer the fan comes on correctly

The point of a power probe is that you connect it to your battery and you can then supply power to motors to ensure that they actually do work.

Tony.

 

[handsomejackuk]

low speed fan works ok as proven by shorting relay contacts on relay socket.. just need to find a 1.9 m44 schematic, as i have been working off the 6 cylinder which is slightly different.. and find out why the low speed realy doesnt come on relay tested and all ok.... suspect there may be a break in the cable between the rad temp sensor and the relay coil connection.... or maybe a fuse....

 

[deni2s]

All z3 electric troubleshooting manuals are available here:
https://www.drive2.ru/l/3138409/

 

[handsomejackuk]

ok thanks....

 

[Nodzed]

i dont really know if the airconditionning is working properly.

Al, I don't mean to state the obvious but if it ain't ice cold it ain't working properly

 

[handsomejackuk]

grrrr it aint working properly then hehe.....prob needs regassing...

 

[Nodzed]

grrrr it aint working properly then hehe.....prob needs regassing...

Make sure its pressure tested before re gassing, the gas doesn't just evaporate regardless of what some AC cowboys will tell you, go to a reputable AC company. Also they should advise you to fit a new dryer, saturation is the biggest cause of failure after the system having a leak.

 

[handsomejackuk]

i had a fella come to the house when i had my saab done, and got to say he was very good, pulled the gas out with vacuum pump, weighed the gas as it went in checked for leaks, and oiled the compressor, cost me £50 and was real good after.... so probably use him... when i am ready...