My car has a R1 engine with polo rad and an electric fan which comes on automatically in traffic. It come son at about a dash indicated 97 deg ish!
I have a savage swtch (pic of a fan) which is wired in so much as it lights up, however the infamous BEC Centre never wired it to actually control the
fan as an over ride, say the ECU does it! So why buy, wire, install give me a switch then dickhead?
Anyways, how would i go about wiring this in? Would i need to splice into the fan wires and drop in new cable to power it fromt he switch?
97 degs sounds about right, 110 degs is getting high, mind it’s pressurised to go over 100 degs
Ain’t that fan switch meant to be for a demister? Suppose if you decide to fit one, which you need for the MOT if you had a windscreen
This temperature thing comes up quiet a lot it seems, probably cos production cars don't tend to have numbers on the gauge, just coloured
bars.
[Edited on 18/1/10 by Mr Whippy]
Im pretty sure it was bought for and is meant to be for a fan over ride.
Have no windscreen and it would be a nice control to have in traffic
You need a 3 position switch:
Position 1: Controller on
Position 2: off
Postion 3: bypass controller (power straight to fan)
if it comes on itself at the right temp then no problem. If you make it manual I can guarantee at some point you'll forget to turn it on, I know
people who have does this 
Especially if it’s the ECU that’s controlling the fan, it'll be part of the programming and the mixture will be getting leaned out as the engine
gets hot (my bike does this) to reduce emissions. Like I said there isn't an overheating problem anyway.
Over cooling the engine will lead to increased carbon & soot deposits on the valves and cylinder head plus reduced power and increased fuel
consumption.
He's not after changing to manual, just providing a manual overide.
i cant remmebr if the ecu provides earth or 12v, you would need to check.
you then wire a one side of the switchg into the wire from the ecu to the relay and the other side of the switch to the same source as the ecu
provides (gnd or 12v)
ig if the ecu is switched ground, you would wire ground > savage switch > into wire from ecu to relay, this will activate the relay when the
switch is on but allows the ecu to also turn it on, as the ecu and switch provide the same voltage it wont damage the ecu.
make usre you get it correct though or you will probably pop the fan circuit in the ecu.
quote:
Originally posted by Richard Quinn
He's not after changing to manual, just providing a manual overide.
quote:
Originally posted by Mr Whippy
quote:
Originally posted by Richard Quinn
He's not after changing to manual, just providing a manual overide.
Dead easy - Just do this wiring replacing the lamps with the fan motor. Don’t wire the switch directly as it will explode or burst into flames with that much current.
On the 03 R1 the ECU goes to ground to start the fan.
To fit an overide
find the fan relay,
find the wire that goes to ECU,
splice a wire into that one and run it to your switch (to check it put the spliced wire to ground and fan should start).
Run a wire from the other side of your switch to ground and hey presto you should have an overide.
Cheers guys, will take a look, I know if its aint broke fix it, but also would be good to have it working in the summer.
yup - its an '03 5PW
Hi mate i took this advice when i did my over ride switch using the bikes fan relay, took the pic from a previous post hope they dont mind
for 02-03 model by taking the green/yellow to earth
0203 Fan Overide
here is the actual thread if you wanted to have a read HTH Greg
97 is about right the coolant won't boil until 120+c.
Best not to add complexity to the wiring which only like to make less reliable, if you want the fan to cut in earlier fit a lower temperature switch,
well as stated yesterday, fitting a fan over ride is not necessary even in summer as the fan comes on at just the right temp and will do then too, so switching on the fan manually will be off no benefit whatsoever and infact over cool the engine which isn't good for it.
I have done the same thing for my megasquirt controlled fan.
The ECU switches the relay to ground to complete the circuit. I just split the switched ground wire and ran it to a switch on the dash. Connected the
other side of the switch to ground and heypresto.
Switch will override ecu and allow fan to be switch on manually in traffic etc.