just took my bike out of the shed after 15 plus years in south Florida . She is UK edition i brought with me in 1999 . All fuel system serviced and she started like a dream yesterday . The cooling fan system i need to know how it should work , when it should turn on . The temp sensor what resistance should i see ? I believe it is triggering the ground to the fan relay ? The relay though doesn’t toggle even if i bypass the temp sensor . Also should i run a different sensor being in hope south florida ? She did used to boil over in traffic sometimes . Now i have the engine running i need to work on the brakes , can the calipers be rebuilt or just buy new ? Anything else after sitting so long ?
Hiya Matthew, all I can tell you is that the fan on mine is coming on around 103 c , and if it's boiling over the pressure in the system cukd be low due to a leak suspect the radiator cap first.
If it's a T595 the fan on temp is more likely to be 106C - from about 99 they changed to 103C) The Temp sensor feeds into the ECU; the ECU processes the sensor reading to: 1) Provide output for the analog gauge 2) Provide a fan enable which is a ground sink through the ECU from the fan relay to turn on the relay for the fan itself; switching positive power, which originates prior to relay from Fuse #5. The Coolant Temp sensor has high resistance when cool (~ 2.5K ohms at 20 C) and low resistance when hot (maybe 200 ohms or so, but not sure what specific resistance relates to 106C) The simplest way to check for fan control is just to run the engine at idle and fan should kick on; another interesting feature is that there is somewhat of hysteresis effect of the temp on the fan; the shut-off temp is much lower than the 'on' temp obviously and additionally, the fan-on temp for 'drive' is much lower with the ignition OFF! So it is actually possible for the fan not to be on, then you shut ignition and fan will start to run!!! You don't have to change anything just because you are in warm climate - the fan will kick on at 106 COOLANT temp, whether the ambient temp is 20 or 40C!!! When moving, the fan is almost never on - the exception is when in slow moving traffic, or stopped at excessively long light. And changing the temp sensor isn't going to help - it needs to report exactly what the ACTUAL temp is. However if you want to change the engine temperature at which the fan comes on, you can actually program this variable via TuneECU to write the new value in the ECU map.
