LINKPlus G3 Ecu Experts, help needed for fan control please :)

[RyanRs]

I have a couple of 10" SPALs on my BMIC to which i would like to be switched on by the ecu. I currently have a relay running to a ign live; the problem with this is that the fans will run before and whilst cranking, suverely reducing cranking power! I know icould wire them into a switch at the dash but tbh i have had the dash apart so many times and added so many new wires along the sides of the car, i would really rather not have to pull it apart again!

So, could i use the G3 LinkPlus to control the relay? I would like the fans to either come on when the revs are above say 900 rpm (so not while cranking) Or set them to come on at a certain Coolant or IAT temp?

How would i go about doing this?

Thanks

[T.F.S.]

on my G4 it has the option to wire to a spare output, you will need a laptop/PC to do it

[Wingers]

I have a G3 LEM and have that set up as you've described. It should be the same for the LinkPlus.

You can set one of the outputs to be a "GP Output" and then specify certain conditions to be met for it to activate. EngineCoolantTemp > 60 degC and RPM > 500 rpm would make sense to me but you can of course set these values to anything you want.
You then need to wire the relay such that it receives +12V when the ignition is on (there is a pin for this in the Link breakout loom) and the ECU will provide the earth when the required conditions are met.

It's not that complicated to do and the help function within the Link software is very useful, but I suppose it depends what (if anything) you've done before.
Feel free to send me a pm if you can't work it out.

Wingers

[RyanRs]

Thanks for the info, TFS -yep got the laptop and software all set up, i always back up my maps with it and tinker about tweeking the settings etc.

I am not majorly clued up with the ecu, i couldn't map it put it that way, but i did fit my own 1zz Cop conversion which included making my own loom, swaping some pins on the ecu and configuring the software -outputs and ign settings, which i would guess is going to be considerably more advanced than wiring up a fan relay! lol

So, i can take a +12V off the ECU , Perhaps the main +12v in? i think its one of the first 4 pins? and then the earth will be wired to an AUX Output? would this be a digital or analogue output?

Thanks

[T.F.S.]

sounds like the guy above knows more than i do lol, im not great with ECU's...i didnt manage to sort the timing reference out when i fitted my COP's so had to revert back to stock until i see the mapper again

but hey your only round the corner from me, maybe we should meet up and exchange knowlege

the help menu is pretty dam good and should show what pins you can use for the fan output, after that you just need to configure it in the settings which seems to be fairly straightforward

[SFLee]

output usually is 0 volt until your ecu set it to come on

ecu output wire to trigger of the relay
voltage direct from fusebox to relay (with a inline fuse)

depend how many output you already using,

PS ECU voltage is control in circuit, so only use it as trigger, if you use to drive a high amp device it may kill your ecu

Lee

[Wingers]

I don't think there is a distinction between analogue and digital outputs (although there is for inputs). The LEM doesn't anyway.
You should be able to use any "Auxiliary Output" for this.
I've set mine up as follows:


As for the wiring, that should be as follows:
+12V switched ---> (~2A) Fuse ---> Relay coil --->ECU "Aux Output"
+12V ----> (~30A) Fuse ---> Relay load ---> Earth

You can use the (permanent) +12V supply from the main fuse box for the fan side of the relay, but you'll need to take a switched +12V for the relay coil. If you use the main live from the fuse box for the relay coil then the fans will come on whenever the ECU shuts down. Check with a multimeter but you should be fine to use the same wire as feeds power to the ECU.
It sounds like you're more than capable of finding that if you've made the loom yourself though.

The ECU can provide a ground for the relay switch, but as mentioned above it will only accept a low current. Check in your LINK manual to be on the safe side but for reference, my ECU can can deal with a relay provided the resistance of the coil is 7A or more. The relay coil will be plenty more than that but again, check it with a multimeter. (disclaimer over )

I'm sure i've made it sound harder than it is but I couldn't face trying to draw circuit diagrams in paint!

Wingers

[RyanRs]

Nope, understand that perfectly! thanks very much for the help

Its probably really simple but tbh tinkering with the wiring on the ecu is still fairly new to me so i just want to be sure that i dont kill £1k's worth of ecu just because i couldn't be ar$ed to run a fan switch in the cab!

Anyways, for the Cops, i used the old Coil switched live. Could i Tee off this wire? I am just concerned that the fans may cause oscillations in the current to which may effect the functioning of the Cops ?

[Wingers]

sorry - you've lost me there.
What is/are Cops?

Wingers

[Marf]

Coil On Plug.

[Wingers]

Ah OK.
It's probably ok but just check that it sits at 0V with the ignition off and goes to 12V with the ignition on.

Wingers

[RyanRs]

Coolies, ill give that a whirl at the weekend me thinks