| Author | Message | ||
     Mark_weiss |
Caught in traffic, barely moving, the 'ol leg roast routine began. It's only April, but the temperature was in the mid-80s and it was even hotter in traffic. I noticed, when the fan switched on, that the heat roasting my leg greatly decreased. With the fan running, a large percentage of the heat was drawn out the back. Now, how to wire in a switch to turn the fan on whenever desired. My thought was that all I'd need to do was find the fan relay and splice in a parallel switch. Imagine my dismay when I noted that the wiring diagram shows no relay. It appears that the fan receives power directly from the ECU. It would seem that sending unexpected power directly into one of these wires might not be the best idea. The ECU decides to start the fan based on the signal received from the cylinder head temperature sensor. Does anyone know how the sensor triggers the fan? Is it like an overheat light in a car? A simple grounding switch, or does the sensor send voltage to the ECU? Mark in Arizona | ||
| Andrejs2112 |
Are you going to try to make it turn off or on? My fan constantly runs if it's warm out. | ||
| Froggy |
There is a head temp sensor on the rear jug, if it gets to a certain point, it says to the ECM, "Hey, were dying here!". The ECM then tells the fan to do its thing, and can vary the speed of the fan based on the temp. I have seen the fan rigged up to turn on whenever the flash button is held, but I do not know the proper way to wire it. | ||
| Hughlysses |
Mark- If you take your seat off, you can see that when the fan's not running, most of that hot air comes from an opening in the frame above the rear cylinder head on the right side. When the engine is hot and the fan's not running, hot air from the rear cylinder head comes up through this opening and "leaks" out along the right side of the seat between the seat and the frame, cooking your right leg. You can either force the fan to run, drawing this hot air out that way or you can block this air opening. I've seen two ways of preventing the hot air "leakage". I cut a piece of adhesive backed aluminum foil HVAC tape to cover the opening and installed that. Someone else here got a piece of automotive weather stripping and stuck it to the bottom side of the seat along the right side. Either fix seems to work pretty well. | ||
| Teeps |
Under parade conditions the fan should come on and stay on. The fan on my Uly comes on between 7.5 and 12 miles from a cold start under city (stop/go) driving. After a hot soak restart, it comes on in about 5 miles. The only 2 conditions I've experienced it turning off are several miles of downhill riding (non aggressive) or turning off the IG1 input. Connect your bike to ECM spy and check the head temp. Sounds like the sensor could be failing (though I've never heard of one failing.) | ||
| Treadmarks |
In really bad traffic, on a hell hot miami day, during rush hour when nuthin is moving..... This can not be beat:  More here. | ||
| Mark_weiss |
The oil cooler fans look very good and I might go that route in the future. What I am interested in for now, is NOT that the engine gets too hot, but that I get too hot. The reason that I want to trigger the fan is to pull heat away from my right leg, added engine cooling is just a bonus. What I would like to find out is how to safely trigger the fan. If the head temperature switch is just a simple grounding switch, then I could easily rig a direct line to ground, parallel to the temperature sensor. The service manual does not describe how the sensor works, I don't even see a test. With the fan wired directly into the ECU, I'm reluctant to play with those wires. I'd rather find a way to tell the ECU that the bike is hot and needs the fan to run. Mark in Arizona | ||
| Froggy |
Problem with fooling the sensor is making not think its too hot, after it gets to a certain point the bike will go into skip spark mode to cool the engine. It does this by causing an intentional misfire every other cycle. | ||
| Ronmold |
Use a relay SPDT ( bosch style automotive) break blk/o wire that goes to fan and run to 87a, run other side of blk/o (the wire that goes to the fan) to 30 and ground 87 & 86. when 85 goes 12v+ ECM is disconnected & fan powers up. | ||
| Electraglider_1997 |
Tread, How much do they cool the oil? | ||
| Mark_weiss |
That's what I was looking for. Trigger the fan, protect the ECU! Just to be certain: The the fan is normally hot, the ECU provides a ground? Thanks Mark in Arizona (Message edited by mark_weiss on April 20, 2009) | ||
| Skinstains |
I forgot where I got the 12 volts from but I just ran it through the "flash to pass" switch and disconnected the headlights from it. I use it all the time when stuck in NYC traffic I can't squeek by. It trips a warning light in the cluster but the light goes out when I let the switch go. I was thinking about using two fans like Treads has but I was gonna put one in each airscoop (I have the large right side scoop American Sport Bike sells). The flash to pass switch was easier so that's what I did. | ||
| Froggy |
Yea Skin when me and Nic plugged in ECMspy it was throwing a code for a bad ground with the fan, but obviously nothing to worry about. | ||
| Ronmold |
Yes ECM provides ground in varying amounts (speeds) | ||
| Skinstains |
Yeah man, I love it and will be modding the Uly soon. Maybe I should change my screen name to "coolbreaze". |
