Radiator fan switching

[TRD_ZERO]

How is the radiator fan switched on a ae111 blacktop?

I've installed a link atom. While running the car the tuner asked me how the fan is switched. I haven't got a clue as the wires that go to the old ecu labeled cooling fan end electric fan are not connected to anything just still sitting in the old ecu plug.

The fan does switch on at 95 degrees according to the tuner but that's pretty late.

What to do any ideas? I know I could just run a manual switch but don't want to.

[Stu-]

Alot of Toyotas have a normally closed sensor on the thermostat housing which opens when up to temp triggering a relay - stock ecu doesn't play a part.

[TRD_ZERO]

So it's working as normal then? 95 degrees seems a little hot for the fan to be coming on that late.

[matt dunn]

So it's working as normal then? 95 degrees seems a little hot for the fan to be coming on that late.

Yeah that is normal.

I have my radiator fans on my race car controlled by the link and they are set to 96 deg.

If you want you can take the single wire that goes to the plug on the radiator side of the thermostat and extend it and connect it to the link,
and then control it how you want.

[TRD_ZERO]

I'm pretty limited with the atom. But as long as it's normal then I'm not too worried. I'll just keep an eye on the temp as my fan isn't located in the best place.

[d1 mule]

I'm pretty limited with the atom.

shit yarn....

you are limited by the number of inputs / outputs not what they can do....

sounds an awful lot like the guy that wired it up / tuned it CBFd wiring it to the ecu

[TRD_ZERO]

No no I did most of the wiring he just double checked it changed a few things before startup. We will be road tuning soon so will look into it again.

[allencr]

The factory fan on it probably isn't controlled by engine temp. or the ECU, just like every other elec. fan except for the ones that are always on with the AC, it is controlled by the coolant exiting the radiator, the only simple way it knows that there is insufficient air flow.

[iOnic]

Who is your tuner? 95 degrees is about right for a fan to cut in. The fan is only there to provide airflow when you're stationary/slow moving and temps start to climb so it's normal for it to be set a bit higher than the temperature that your thermostat is trying to maintain. You can set it lower if you want to but there is only ~5deg between your thermostat temp and your fan temp so you're more likely to achieve a fan that comes on at operating temp and stays on than anything else by lowering it.

I personally wouldn't bother wiring it into the ECU - you just lose another output that could be better used elsewhere. It works perfectly fine on the temp switch.