Fan control

[Stranger24]

Hi Guys,

 

Could you give me some hints on how to setup fan control for my e36?

 

E36 uses viscous fan and I deleted this and bought mishimoto radiator and electric fan without controller.

 

I plan to use the wiring from the ac control as removed all AC system . any advice or hint is appreciated 

[Vaughan]

You'll need to use a relay to supply the power to the fan and you can use any Aux to trigger this, Ignition 7 was used to trigger the AC relay so you can reuse this and you may be able to reuse the AC relay as well depending on how it is wired.

[Stranger24]

Thanks that is what I thought re relay as ac fan is quite beefy and big so must have a relay and if I can reuse wiring.

 

so ignition 7 becomes what under the program? I am trying to understand how I get link ecu to read the water temp from rad sensor not the main water temp sensor. 

[Vaughan]

Are you using a plugin or a wirein ECU? it looks like the plugin ECU isn't wired to a radiator temperature sensor at all. Also are you sure it is a temperature sensor in the radiator not a temperature switch?

[koracing]

You would still use the engine coolant temp and not the rad water temp typically with ECU control - you can program whatever temp for it to come on that you want.  Assuming the AC relay wiring is suitable to use to trigger the Fan relay, you would change the base calibration settings as follows:

Change from: Chassis and Body Control -> AC Clutch Control -> Ouput Ign 7 -- To: Auxiliary Outputs -> Engine Fan -> Engine Fan 1 Output -> Ign 7

[Stranger24]

Thanks all

 

that doesn’t seem to work. Here is my findings . I think i ac clutch relay on ign 7 is to turn compressor on and not for the fan

 

I have reallocated ignition 7 on the ecu to engine fan and can confirm it powers the ac clutch relay however no power on the pins connecting to the aux fan, i am wondering does that mean compressor  and its not the fan, pretty sure feels that is what it means.

 

I can hear the relay tick sound however no power is getting to the wiring/ 3 pins which were used for ac fan/aux fan

I then removed the radiator temp switch and connected ground to 12v and can see power on the three pin which connects to the ac fan/ aux fan.

I am trying to now understand what is that temp switch wiring to the ac fan . Does that mean when you request ac, fan won’t come on and only comes on when rad is too hot and pressure switch shorts?

 

there are three pins on pressure switch and 3 pins on fan control wiring. 1 power and 2 ground on temp switch and 2 power and 1 ground on fan wiring

 

depending on what ground you short to the 12 v, you get a different power cable on the fan side.

 

Below is the wiring diagram I could see, not great at reading / understanding however thought I paste in case anyone is good with this

[Adamw]

The stock fan is not controlled by the ecu at all, the "normal speed" relay gets its on/off signal from the AC unit or temp switch, part of the temp switch and pressure switch also swap the fan from normal speed to high speed depending on temp and ac pressure. 

The compressor control relay is not suitable for controlling a fan as it only has a 7.5A supply.  

If you want to control the "Normal speed" relay with the ECU instead of the temperature switch, then I would cut the Ign 7 wire off the compressor control relay where I have put the blue line.  Also cut/disconnect the temp switch from the Normal speed relay (I have shown as a blue line cut also).  Then connect the Ign 7 wire to where the temp switch originally connected to the normal speed relay (shown as pink line).  

 

[Stranger24]

Thanks Adam appreciate your input and time taken to explain.

 

given I have a mishimoto fan which doesn’t have low/ high speed, i guess any 12 v whether normal or high speed will provide max power to the fan?

 

i will go and do some digging to find the wires you mentioned. I am little clueless reading diagrams 

 

ign 7 to ping 86 of the normal speed relay?

[Adamw]

Yes you could use either the high speed or normal speed relay to achieve the same thing, just need to connect the right one to the fan.  

 

12 minutes ago, Aram said:

ign 7 to ping 86 of the normal speed relay?

It appears to be a special 5pin relay with 2 "triggers" so I dont know if it has the standard ISO footprint and pin numbers.

[Stranger24]

Thanks again @Adamw

 

you are a legend.

 

here is how I did mine in car anyone bumps into same issue.

 

opened the fuse box under the bonnet, took wire 86b on second relay which is blue/black to either black and yellow or black and green on first relay. Problem solved. 
 

thanks again Adam