Radiator Fan Switch
#11
12-06-2017, 12:05 PM
Funny part... KLX300R and KLX650R off roaders... no fan. I did see there may have been fans on the Aussie 300 at one time.
Either way, I have never seen or heard of a manual bypass switch set up in the aftermarket. Probably because all you have to do is find which wire is the ground for the fan, then wire a switch in it. I know this because I had the fan on my 650 running at intervals for extended periods. Seemed I pinched the ground between the shroud panels and it finally wore through, contacting at times.
Either way, I have never seen or heard of a manual bypass switch set up in the aftermarket. Probably because all you have to do is find which wire is the ground for the fan, then wire a switch in it. I know this because I had the fan on my 650 running at intervals for extended periods. Seemed I pinched the ground between the shroud panels and it finally wore through, contacting at times.
Manual Fan Bypass Switch
https://www.ebay.com/itm/252077711779
#12
12-06-2017, 12:18 PM
Since I'm an elec eng registered in 4 states, I'll take this one.
My bike is an USA 07. The radiators are piped in series with the water pump serving engine, the left one served from the engine into the bottom and it serves the right one at the top, then out the bottom back to the pump. There are two sensors, one in each radiator, although the wiring diagram indicates only one. One of these may be the high temperature light, you will need to research this as I didn't look for that sensor. If one is for the high temp light, ignore the parallel/series discussion below.
Regardless you would only need one sensor as it is the same water. I would activate the one on the left as that will be the hottest water. It looks like the temp sensors ground the fan relay causing it to start. Since the wiring diagram only indicates one sensor, and 2 are installed, who knows if these are wired in parallel or series. If they are parallel, you could just add one, if they are series you would have to have 2 or connect the wires together on the one that is disabled. You can test this by turning the bike on and connecting the wires on one sensor, if the fan starts they are in parallel.
My bike is an USA 07. The radiators are piped in series with the water pump serving engine, the left one served from the engine into the bottom and it serves the right one at the top, then out the bottom back to the pump. There are two sensors, one in each radiator, although the wiring diagram indicates only one. One of these may be the high temperature light, you will need to research this as I didn't look for that sensor. If one is for the high temp light, ignore the parallel/series discussion below.
Regardless you would only need one sensor as it is the same water. I would activate the one on the left as that will be the hottest water. It looks like the temp sensors ground the fan relay causing it to start. Since the wiring diagram only indicates one sensor, and 2 are installed, who knows if these are wired in parallel or series. If they are parallel, you could just add one, if they are series you would have to have 2 or connect the wires together on the one that is disabled. You can test this by turning the bike on and connecting the wires on one sensor, if the fan starts they are in parallel.
#13
12-06-2017, 12:40 PM
This one has been around for years now. A few here and on ADVrider have them.
Manual Fan Bypass Switch
https://www.ebay.com/itm/252077711779
Manual Fan Bypass Switch
https://www.ebay.com/itm/252077711779
Some people carry umbrellas on sunny clear days too. I used to carry a rain suit in my tank bag all the time, two years before I actually had to pull it out and use it. I considered it a good luck omen j- carry the rain suit and never have rain. But I didn't put it on until there was proof I needed to.
Maybe a switch might make sense if the switch was wired in parallel with the sensor, that way you could keep the sensor working and have the switch for back up. Kind of like my rain suit, use the switch should the temp light come on or if there are clear signs of possible overheating. But unless you really know what you're doing, having a manual fan switch might have you running the engine too coo, which is not good for it.
If I was really concerned I'd be figuring out if I could set up a temperature gauge. Maybe one of the digital dashes have a temperature gauge, all it would take is the right sensor to keep track of temperature versus an on/off switch for a light.
With 50,000 on a KLX650 the only time I ever had the fan come on was if it was a really hot day and was turning around (not moving much) or stuck in a rut. It might start up and run for maybe 30 seconds. On the road, same deal 90 degree day sitting in traffic for minutes at a time. The only other time was when I pinched the sensor wire causing the fan to run at random when the wire would ground out. Seems the sensor will complete the circuit when the coolant reaches a specific temperature. That was a treat to figure out. The 250 fan, I forget if I've heard it run. Entirely possible it's never heated up to the point to do so, I don't remember. Plus the dual radiators make for a lot of cooling surface.
Speaking of what NOT to do, in that ebay ad it looks like they drilled a frame member to attach the switch. Another place slightly weakened with possible stress risers to develop a crack if the frame is stressed enough there. Sometimes ya kinda wonder.
Last edited by klx678; 12-06-2017 at 12:51 PM.
#14
12-06-2017, 01:49 PM
Since I'm an elec eng registered in 4 states, I'll take this one.
My bike is an USA 07. The radiators are piped in series with the water pump serving engine, the left one served from the engine into the bottom and it serves the right one at the top, then out the bottom back to the pump. There are two sensors, one in each radiator, although the wiring diagram indicates only one. One of these may be the high temperature light, you will need to research this as I didn't look for that sensor. If one is for the high temp light, ignore the parallel/series discussion below.
Regardless you would only need one sensor as it is the same water. I would activate the one on the left as that will be the hottest water. It looks like the temp sensors ground the fan relay causing it to start. Since the wiring diagram only indicates one sensor, and 2 are installed, who knows if these are wired in parallel or series. If they are parallel, you could just add one, if they are series you would have to have 2 or connect the wires together on the one that is disabled. You can test this by turning the bike on and connecting the wires on one sensor, if the fan starts they are in parallel.
My bike is an USA 07. The radiators are piped in series with the water pump serving engine, the left one served from the engine into the bottom and it serves the right one at the top, then out the bottom back to the pump. There are two sensors, one in each radiator, although the wiring diagram indicates only one. One of these may be the high temperature light, you will need to research this as I didn't look for that sensor. If one is for the high temp light, ignore the parallel/series discussion below.
Regardless you would only need one sensor as it is the same water. I would activate the one on the left as that will be the hottest water. It looks like the temp sensors ground the fan relay causing it to start. Since the wiring diagram only indicates one sensor, and 2 are installed, who knows if these are wired in parallel or series. If they are parallel, you could just add one, if they are series you would have to have 2 or connect the wires together on the one that is disabled. You can test this by turning the bike on and connecting the wires on one sensor, if the fan starts they are in parallel.
Yeah gotcha, I was thinking about installing the switch on the left one as well. Now I hope I can find a good (priced) after market one with the right thread size.
#15
12-06-2017, 02:39 PM
On my '06, left sensor is over-temp warning light.
Right sensor is fan operation. I installed a bypass switch on the fan circuit to operate the fan manually.
Click the FAQ link in my sig line to research further. Search "fan"
Right sensor is fan operation. I installed a bypass switch on the fan circuit to operate the fan manually.
Click the FAQ link in my sig line to research further. Search "fan"
#16
12-11-2017, 08:25 AM
No problem, I could use the same hole and just install a switch instead of a sensor. I'll wire it as shown in the wiring diagram from the KLX250H6F.
However I'm having issues finding a switch in M10x1 thread size. Any ideas where I could find one?
#17
12-17-2017, 06:41 PM
When I look at the switch that I removed it seems that it only has one port. After a bit of research that indicates that the switch was not a switch but actually a sensor (correct me if I'm wrong).
No problem, I could use the same hole and just install a switch instead of a sensor. I'll wire it as shown in the wiring diagram from the KLX250H6F.
However I'm having issues finding a switch in M10x1 thread size. Any ideas where I could find one?
No problem, I could use the same hole and just install a switch instead of a sensor. I'll wire it as shown in the wiring diagram from the KLX250H6F.
However I'm having issues finding a switch in M10x1 thread size. Any ideas where I could find one?
The one on the right is the fan switch.
#18
12-18-2017, 04:17 AM
bit off topic, but may I ask why you chose to fit a manual switch? I might have to go down that path but just a on/off switch compared to your on/off/normal switch.
#19
12-18-2017, 02:50 PM
I don't know thread size.
My fan would kick on like it should on hot days, slow riding, usually up a tight single track. Then it stopped working so well. I replaced the OEM switch and it didn't seem to make a consistent difference, so I put in a switch. If you see my notes in the FAQs, I used a SPST on/off switch and not the three-way listed in the hand-drawn diagram. This way it works normally (via the OEM switch) or on. I run a TrailTech Vapor computer and watch temperatures with two separate warning temperature lamps and pay attention to temps. I'll kick the fan on during hot days when I'm riding slow single track climbs or other times when the Vapor indicates temperatures approaching 200-205F.
My fan would kick on like it should on hot days, slow riding, usually up a tight single track. Then it stopped working so well. I replaced the OEM switch and it didn't seem to make a consistent difference, so I put in a switch. If you see my notes in the FAQs, I used a SPST on/off switch and not the three-way listed in the hand-drawn diagram. This way it works normally (via the OEM switch) or on. I run a TrailTech Vapor computer and watch temperatures with two separate warning temperature lamps and pay attention to temps. I'll kick the fan on during hot days when I'm riding slow single track climbs or other times when the Vapor indicates temperatures approaching 200-205F.
#20
12-22-2017, 12:02 AM
Some people carry umbrellas on sunny clear days too. I used to carry a rain suit in my tank bag all the time, two years before I actually had to pull it out and use it. I considered it a good luck omen j- carry the rain suit and never have rain. But I didn't put it on until there was proof I needed to.
Maybe a switch might make sense if the switch was wired in parallel with the sensor, that way you could keep the sensor working and have the switch for back up. Kind of like my rain suit, use the switch should the temp light come on or if there are clear signs of possible overheating. But unless you really know what you're doing, having a manual fan switch might have you running the engine too coo, which is not good for it.
If I was really concerned I'd be figuring out if I could set up a temperature gauge. Maybe one of the digital dashes have a temperature gauge, all it would take is the right sensor to keep track of temperature versus an on/off switch for a light.
With 50,000 on a KLX650 the only time I ever had the fan come on was if it was a really hot day and was turning around (not moving much) or stuck in a rut. It might start up and run for maybe 30 seconds. On the road, same deal 90 degree day sitting in traffic for minutes at a time. The only other time was when I pinched the sensor wire causing the fan to run at random when the wire would ground out. Seems the sensor will complete the circuit when the coolant reaches a specific temperature. That was a treat to figure out. The 250 fan, I forget if I've heard it run. Entirely possible it's never heated up to the point to do so, I don't remember. Plus the dual radiators make for a lot of cooling surface.
Speaking of what NOT to do, in that ebay ad it looks like they drilled a frame member to attach the switch. Another place slightly weakened with possible stress risers to develop a crack if the frame is stressed enough there. Sometimes ya kinda wonder.
Maybe a switch might make sense if the switch was wired in parallel with the sensor, that way you could keep the sensor working and have the switch for back up. Kind of like my rain suit, use the switch should the temp light come on or if there are clear signs of possible overheating. But unless you really know what you're doing, having a manual fan switch might have you running the engine too coo, which is not good for it.
If I was really concerned I'd be figuring out if I could set up a temperature gauge. Maybe one of the digital dashes have a temperature gauge, all it would take is the right sensor to keep track of temperature versus an on/off switch for a light.
With 50,000 on a KLX650 the only time I ever had the fan come on was if it was a really hot day and was turning around (not moving much) or stuck in a rut. It might start up and run for maybe 30 seconds. On the road, same deal 90 degree day sitting in traffic for minutes at a time. The only other time was when I pinched the sensor wire causing the fan to run at random when the wire would ground out. Seems the sensor will complete the circuit when the coolant reaches a specific temperature. That was a treat to figure out. The 250 fan, I forget if I've heard it run. Entirely possible it's never heated up to the point to do so, I don't remember. Plus the dual radiators make for a lot of cooling surface.
Speaking of what NOT to do, in that ebay ad it looks like they drilled a frame member to attach the switch. Another place slightly weakened with possible stress risers to develop a crack if the frame is stressed enough there. Sometimes ya kinda wonder.
Ah, I only posted that link cuz you said you’ve never seen any for the KLX. I don’t have one, the bike doesn’t need one since it runs so cool. I’ve only had my fan go on 1 once in over 3 years, about 3,000 miles. All the other bikes I ride with, they all happen to trip the fan on constantly. I had tested mine to make sure it works though. I know it feels weird that everyone else’s fan are running, and mine never runs, that something is wrong with it. But this bike had a great cooling system as a 300cc, now even more efficient as a 250cc. If anyone is worried about it, they should get a Radiator Cap that has a temp gauge in it just so you can keep an eye on it just be sure. Good investment and a little Peace of Mind for $30 bucks. Many companies have them. Tusk, IMS, OutLaw Racing, etc.
Outlaw Racing OR3126 High Pressure Temperature Gauge Radiator Cap Honda Suzuki Yamaha Kawasaki Motorcycle ATV
Last edited by Werloc; 12-22-2017 at 12:19 AM.