I am looking at running the thermo fans off the EMS instead of the standard ECU. That way I can run one calibrated temp sensor straight to the EMS, rather than piggybacking the standard ecu, or running two sensors.

Checking out the wiring diagrams and ecu pinouts finds 4 triggers from the ecu running to 4 relays as follows:



So from that when triggered:

Relay 1 = LHS Fan on, RHS Fan on

Relay 2 = LHS Fan on, RHS Fan on (possibly high speed??)

Relay 3 = RHS Fan on

Relay 4 = Grounds LHS Fan

Relay 1 or 2 & Relay 4 = LHS Fan on


There is 4 programmable outputs from the EMS that would suit triggering the relays (the thermo relays are a pull to ground trigger) they can be programmed for on/off by multiple sources eg: temp, revs etc set up with if/and parameters

Does anyone know what the standard ecu's parameters are for the thermos?? eg: what temp does one come on, what temp for the second etc?? or suggest a good temp range?

Also what other events can trigger the thermos? eg: aircon?

Anyone got any info or suggestions?

Cheers

I remember them coming on regardless of coolant temp when the a/c was turned on.

Was that just at idle? or whilst moving as well.

Sitting still...that was a way of testing if the fans were ok as well as the relays.
They came on flat out, too.