Radiator Switch Wiring

[KitsonRis]

Want to run a radiator fan bypass so I can switch the fan on manually, mainly for using it after a track session and the fact that it got silly hot the other day when sat in traffic (I am positive I saw the temp rise then come back down then creep back up, so the fan must have kicked in??)

I have the PMS smaller radiator kit fitted as I am running ITB's in my Ph1 now. I had this fitted by a garage.
I have found THIS thread which says just wire a switch in parallel to it. Sounds simple. In my head it looks like this, but this is bound to be wrong!

So just gone out to look at the car and see exactly what is what and I am a litle stumped. There is what looks like a new connector on the new fan that was fitted (white plug) and then a second plug that was tapped up, assume done by the garage. Looking at the radiator there is no switch on it, from that thread I found there should be one on it?

What is that second plug for (the one with the purple seal on)?

Went back to the PMS website and there is this Fan Controller - is this what I am after?
The only other thing is when I was re-pinning my ECU I had to remove a pin that was the CTS Warning Light out - looking on the spreadsheet supplied from KTec this is the Coolant Temperature Sensor.


Edit: the random plug could be for the air con that has been removed according to THIS thread.
But the question still stands on where I need to wire the toggle switch into??

 

[KitsonRis]

found the coolant sensor, side of the thermostat 🤦‍♂️
But my idea of just wiring a switch in parallel goes out the window as there are three wires going to it....or to put it correctly I hate wiring and can't work it out!

The only other thing I can think of is run a proper over ride and take a positive feed from somewhere, put an inline fuse in it, and then run that directly to the radiator fan with a switch in the middle of it all. But I want to avoid that. But doing some more reading it might be controlled by the ECU. It didn't show any signs of over heating while it was being mapped but then again it did have a massive fan pointing at the car!

 

[Brigsy]

Fan will be controlled by ecu as per oem. Shouldnt need an override if it works right, how hot does the coolant get in degrees?

Is the fan adequate sized? I had a small spal one on my turbo trophy which worked ok on cooler days, but was no good on hot days and temp used to steadily creep up with fan on all the time. I upgraded to a larger high flow comex fan which works fine and ecu cuts it in and out as necessary, ive set ecu to cut it in at 95deg taking back down to 90deg cut off. I could prob go up to 100 deg no problem and 95deg cut off same as meg .

 

[KitsonRis]

I am running a lower temp thermostat and it was running at just below half way normally (1).
I was sat in stationary traffic the other day for about 20mins after a 40min drive and it crept up to about 3/4 on the gauge (2) and then dropped down to half way (3) then slowly crept up to near max (4) (wasn't this hot for long, about 2 mins, but felt like an enternity, stuck in a contraflow so couldn't pull over) and then dropped down to half way as soon as I got going.

I am yet to take the car back out to see what is happening, I just got home and turned it off to cool it down ASAP.

It is a Comex high powered pull one from THIS package. It was working when it was fitted but since then I am running a GEN90 ecu now and this is the first time it has got hot since. I am going to take it on a drive over the weekend to see what I can get out of it to try and get it up to temp and see if it kicks in. But having a manual over ride would be useful for track days though.



Thsi youtube video is about the level of my skill when it comes to wiring and if I could do this I would be happy! Just need to locate the right relay.

 

[Brigsy]

Do some datalogging to see what temp the ecu is reporting, where fan is cutting in and out. Ive no idea how accurate ph1 oem temp gauge is, ph2 is not very accurate.

Unfortunately id say the smaller rad and fan combo is the issue, ok for a short period in traffic but not good in longer stints, as its aimed at track use and adequate for cooling when on the move. Heater on hot and interior fan in full if you get caught in traffic.

Manual override will do nothing on track use tbh. If you want to do anything for cooling after a track session, fit an electronic pump to circulate coolant after engine is shut down.

 

[KitsonRis]

Will try and get some data logging out of it but I don't have any gizmos for this.
If I can prove the fan kicks in when hot then I would be more happy with it, like then I know it is working. From memory before the new rad and that was installed it used to kick in about point 2 on my picture above (oddly on my old Ph1 when the fan kicked in the temp gauge dropped to zero and then kicked back into life when then fan stopped 🤷‍♂️). I will still probably install something as a back up for track days when sat after a session.

It had fresh coolant in but that now needs a flush as it is now brown. One it looks naff seeing as it was all nice and fresh!

 

[Brigsy]

Does gen90 have onboard datalogging? Most half decent ecus have something. If not just watch live coolant temp data on laptop and check fan cuts in. Also most ecus say fan is active when its on.

 

[KitsonRis]

it probably does but I don't have a laptop that will connect to it which was half the problem with getting the ITBs up and running. I wasn't going to buy a second laptop just for this purpose.

 

[Brigsy]

Id get geared up with a laptop to suit, only need a cheapo. You will need to be in the ecu at some point