S4RS cooling fan failure!

[Speeddog]

From my understanding of how the fan sytem is set up on an SBK, I can see that system working on an SBK.
AFAIK, the SBK's use a thermoswitch.

Monster S4 and S4R have the fans controlled by the ECU, which is deciding when to turn the fans on based on readings from a thermosensor.
The ECU also uses the thermosensor data to adjust mixture.
So you can't just 'short' the thermosensor like that to turn the fans on.
Well, you can, but it'll fark the mixture.

I could be wrong.

[djrashonal]

My thought is that I would keep the present system intact and just tap into the wires after the fan relay to complete the circuit. Thus if i forget to turn on the fan manually it will still kick it on @ 216 or whatever it's rated at

[Speeddog]

My thought is that I would keep the present system intact and just tap into the wires after the fan relay to complete the circuit. Thus if i forget to turn on the fan manually it will stick kick it on @ 216 or whatever it's rated at

If the '01 S4 is as I remember, with a fan relay, I think you'd be safe doing that.
My '01 S4 wiring diagram isn't at hand right now....

[CCEMN1]

My thought is that I would keep the present system intact and just tap into the wires after the fan relay to complete the circuit. Thus if i forget to turn on the fan manually it will stick kick it on @ 216 or whatever it's rated at

That's what I had planned on doing, running a completely seperate not line from a switch to the fans themselves, having the ability to turn on both fans at once, manually, but hoping the whole thermoswitch, thermosensor thing will continue to function as normal.
Am I correct in assuming this is doable?

[Speeddog]

Don't know if the S4RS has a fan relay(s), likely not.

Not sure if the ECU would like independently supplied 12V on that circuit.

[ducpainter]

That's what I had planned on doing, running a completely seperate not line from a switch to the fans themselves, having the ability to turn on both fans at once, manually, but hoping the whole thermoswitch, thermosensor thing will continue to function as normal.
Am I correct in assuming this is doable?

I'd be leery of feeding 12V to the fan and leaving the factory wiring going back to anything but a relay.

Ecus have been known to get finicky about voltage and which way it comes at them and the relay would act as a buffer of sorts.

[djrashonal]

If the '01 S4 is as I remember, with a fan relay, I think you'd be safe doing that.
My '01 S4 wiring diagram isn't at hand right now....

I've looked at the s4 book i have but the wiring is generic and not labeled. is there something out there that can confirm this?

[Speeddog]

The printed OEM Owner's Manual will have a wiring diagram, as will the OEM Service Manual.

[CCEMN1]

So, If I disconnect the fans from their existing connections, and just run a mechanical 30 amp switch solely controling them, do you think this will create any problems with the ECU & mapping?

[ducpainter]

So, If I disconnect the fans from their existing connections, and just run a mechanical 30 amp switch solely controling them, do you think this will create any problems with the ECU & mapping?

I'd still use a relay and I doubt you need a 30 amp switch, but as long as you leave whatever sensor the ecu uses to determine temp connected I don't see a problem. The ecu doesn't know if the fans are running, just that it has supplied voltage to them.

[CCEMN1]

You guys have got me nervous about this now, so I think I'll just install the new fan & call it macaroni.
I was just concerned that the coolant Temp was up to 228 with NO fans on at all, and was concerned there was a sensor, or switch problem. Now I'm thinking it may have had something to do with the failing left fan? So, I'll wire it up stock at first and see what happens.
I just don't like hot motors, I know how it shortens the life of everything from oil & bearings to pistons & rings! This is also why I don't like the two valve, air cooled Monsters, it's like taking a giant step backwards into Harley technology!