Wiring question

[Telf 222 2 Cars]

Does anybody know what the plug pictured is for ? It comes from the shunt box - last plug under the fuses and goes to the white plug pictured. Thick red cable in the white plug is marked 57

[jackherer 543]

That's the radiator fan wiring, it should be a separate self contained loom that just connects to ground, the shunt box, the fan, the rad temp sensor and the low speed resistor.

 

If you're using your Emerald to trigger the fan you can throw that loom in the bin.

[Telf 222 2 Cars]

[Andy 105 1 Cars]

Hi. An aside here. If you are using your Emerald to control the fan, then excellent. It does a good job. One small ‘however’, If the fan is running when the ignition is turned off, the fan will stop. Fine, unless the engine happens to be stinking hot at the time. I used the switch on the road to trigger a second relay that was also wired to the fan . This enables the fan to continue to cool the radiator after switch off if the engine is very hot. Just a thought .

 Andy

[jackherer 543]

I'm pretty sure there is a way to wire the Emerald so it stays on while the fan is running, IIRC that's why it has two +12v inputs (pins 11 and 28)

 

I haven't implemented it myself, I just keep the ignition on if the fan is running when I stop.

 

I've also considered replacing the factory switch in the radiator then connecting it to the Emerald fan relay so it has two independent triggers.

[Andy 105 1 Cars]

Hi. Yep. If you wire  the ignition to pin 11 , you can use a switch to ground from another output to switch to live pin 28 . This has the advantage of allowing the ecu to update when the ignition is turned off. However, because the relay which actives pin 28 is grounded via an ecu output, it still  goes off on ignition off , so preventing the fan from continuing to run . Well , at least that was the outcome when I wired mine this way . Fan override via the rad switch is the way forward !

 Andy

[Telf 222 2 Cars]

So... I chopped all the rad switch wiring out earlier... Now I'm thinking if I reinstigate the wiring I can just splice it in after the power output on the relay that I've got connected to the emerald. This way if the emerald swiches the fan first that's all good but if I have a hot engine when the ignition is off the temp bulb rad switch should keep the fan going right? 

 

Or am I missing something?

 

Also I presume I no longer need the temp bulb that sits on the radiator?

[Andy 105 1 Cars]

Hi. The relay that is activated by your Emerald supplies power to your fan . The emerald grounds the relay to activate the fan. So, the easy way for the backup is to take one lead from the fan thermostatic switch and connect it to the grounded pin on the fan relay . Take the other two where from the same thermostatic switch and connect to ground . Then, the Emerald will switch on the fan as planned at whatever temp you programme in , and , in the event of the radiator being above about 92, the thermostatic switch will connect to ground and keep the fan running , whatever the state of the Emerald . The only thing to look for is the connections on the thermostatic switch. This was designed to take a high current live and , at a preset temp, switch this live to the fan via a resistor. If the temp continued to rise , the switch would then change contacts again and connect to the fan without the resistor. So, really, you want that original live feed pin to wire to the grounded pin on the relay , and the other two connected together and wired directly to earth . Then the thermostatic switch behaves like a simple off - on temperature switch which just grounds ( ie activates ) your Emerald fan relay .

 I hope this ramble makes sense .

 Andy

[Telf 222 2 Cars]

So do I still need the resistor or can I just remove it ? That's confusing me a bit

[Telf 222 2 Cars]

Ok so this is how I've wired it. 2 cables from the rad switch to earth. One wired into the switched earth that ones from the ECU. And then the 12 v supply for the relay and the output.

 

This is correct I think?

[jackherer 543]

That looks good to me.

 

The resistor is intended to slow the fan for the first stage of the dual stage operation of the standard switch.

 

The Emerald is only single stage (as is the switch if you link both pins together) so you don't need the resistor any more.

 

The fan will be louder when it turns on but it will turn off sooner.

[Telf 222 2 Cars]

Ok cool , going off Andy's description I thought it seemed right and makes sense. Anyway it's done now!

[Andy 105 1 Cars]

And it is correct . Ditch the resistor as per advice above . 

Andy

[Telf 222 2 Cars]

Cheers for the help guys