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Discussion Starter #1
I have a problem with my fans not coming on when the bike (2006) heats up. I've tested most connections and the relay (all ok so far) and now I need to get at a connector (C13) that is below the air cleaner housing. I have all the screws out but it seems like there is a hose or something at the bottom of the lower housing that is holding it in there.

Does anyone know what is holding it and what the trick is to getting it out?

Also the trouble shooting guide in the Honda manual says to replace the ECM when all the things that I have tested are OK, which they are. But I'm thinking that I will check this connector out first and then check out the temperature sensor which is in the left head.

Has anyone here had any experience with the fans not coming on and what did you find?
 

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Standing on the left side of the bike looking down at the air box bottom. There is a hose on each front corner,the right side hose can be pulled off and put back on by hand. The LEFT front hose is the hard one. We pull the BLACK upper cowl off that is up inside the fairing (several black push pins hold this is) then take some long needle nose pliers to unhook and also when reinstalling this hose. You also have to do this when replacing throttle cables. Fairly easy to do but time consuming. Can't help with your fan problems sorry.
 

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Discussion Starter #3
Thanks Ernhardt. I'll give that a try tomorrow.

I did a search on this board re my problem with the fans and came up with nothing. I hope someone can come up with something. But this may be a unique problem with my bike.
 

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Mike, if you need to take the box completely out, there are two more hoses on the back of the air box. Not sure if you can get to them without removing the gas tank. Also, when you said you got "all" the screws out, not sure if you were also talking about the 4 screws surrounding the two throttle bodies.:shrug:
 

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Have you checked the fan fuse??

The fact that both fans will not operate kinda eliminates a lot of things and points to others.

Once you reach that pin connector there is a wire circuit to each fan, and as both do not work, most likely not that.

Could be the engine temperature sensor. You can take a sharp knife and lay across the wires to the sensor and make sure you make contact with each wire, if it is the sensor the fans should fire. If not then could be a really corroded connector or open wire in the circuit between the relay and that connector.

You can jump wire to the fans also to test the fan motors. Be rare for both to go bad at the same time, do not think that is it.
 

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There are two large crankcase breather hoses connected to the bottom of the air box. The only way I could remove the air box was to also remove the gas tank. It's not too difficult. Remove the shelter. Slide the battery box out about one inch by removing the single bolt under the battery. Release the fuel lines and two connectors. Remove the four bolts holding the tank. You must lift the front of the tank while twisting it to the right side. Be sure to empty the tank first.
:thumbup:
 

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GL1800 Doctor
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There are two large crankcase breather hoses connected to the bottom of the air box. The only way I could remove the air box was to also remove the gas tank. It's not too difficult. Remove the shelter. Slide the battery box out about one inch by removing the single bolt under the battery. Release the fuel lines and two connectors. Remove the four bolts holding the tank. You must lift the front of the tank while twisting it to the right side. Be sure to empty the tank first.
:thumbup:
And there's a hose on the bottom front of the box for the PAIR system that has to be disconnected once you get it to lift up a little.
 

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GL1800 Doctor
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There is another way to ohm out the sensor without getting to the C13 connector. Pull off the ECM connectors and ohm out the 2 wires that go to both sides of the sensor. You will be measuring the resistance of the wires, the C13 connector, and the sensor. Here is the schematic and the wires you will need to ohm out. These are both in the "B" connector, B2 which is a green/red wire and B12 which is a yellow/blue wire. The issue you will have is the specs for this thing calls for removing it from the engine and sticking it in a pot of hot coolant and measuring the resistance. You could get the engine hot, but it will be tricky to get the test results and make sure the engine is at the right temps.

Another thing you can try, if you can find a resistor with the value of .68 ohms, you can put it across those 2 pins of the ECM with it running and the ECM will "think" the ECT is hot enough to turn on the fans. If this works, it eliminates a bad ECM and points more toward the ECT sensor or harness as the problem. But if the ECM still doesn't turn on the fans with the resistor in there, that would point to a bad ECM.



 

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I just ASSUMED you had already removed the gas tank.
 

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Discussion Starter #10
Tech Dude I tried the continuity check you suggested with the engine cold. The reading indicated an open circuit but I wasn't sure whether I should have any resistance measurement with the coolant sensor not activated. Also I didn't think it would be quite feasible to do the same check with the engine hot because I would have to get it hot with the connectors back on the ECM and once disconnected I didn't know what would happen...the engine would have to be stopped and it may cool down before I could make the reading.

So I have removed the left radiator and removed the connector on the coolant sensor and checked for continuity to the ECM plug. There is no continuity. So the next step is to remove the gas tank and check C13 connector. This means I will have to remove the gas tank. So next question:

Is there a something that I can disconnect to drain the tank or should I just siphon the gas out?
 

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I know you asked TechDude but I would siphon at least to half tank and then take rubber plugs to cap off lines. Pull up tank and twist to the right side to get out.
 

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GL1800 Doctor
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I think you should have gotten about 10 ohms on the measurement from the ECM connectors. It sucks that Honda doesn't list the sensor's resistance when cold. Did you check the resistance on the sensor itself? I was just wondering what you would get with it at ambient temp. I'm guessing it would be around 6-8 ohms. Has anything ever been done around the airbox? I wonder how the C13 connection would just open without being disturbed. I would siphon all of the gas out before handling the tank. I just don't like messing with flammable liquids. :thumbup:
 

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Discussion Starter #13
I did not check the resistance of the sensor itself. If I can get at it today I will. Also I had bought a spare sensor some time ago anticipating that I might need it when the fans first quit after the bike was transported to Yuma. I'll see how it compares.

I have never done anything around the airbox other than change a filter several years ago. The only reason for the failure that I can think of is that for the past 4 years I have transported the wing in an open trailer between Vancouver Island and Yuma, Arizona in December and March. Quite often the bike ends up with lots of road dirt on it after the trip. Last year my CB did not work properly after the trip and the problem turned out to be dirty contacts somewhere. I don't know where because I just cleaned them all to fix the problem.
 

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Discussion Starter #14
OK I checked both of the Temperature sensors between pins 1 & 2 (the one currently in the bike and the new one that I bought). They both measure 20 ohms with the engine cold.
 

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GL1800 Doctor
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Ummm, 20 ohms when cold. If you had the right 2 wires in the ECM connector you should have read that or close to it from there. It does sound like there's an issue with the wires running to and from C13. Keep us posted on what you find.:thumbup:
 

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fans not working

I am having the same issue with the fans not coming on with my 2006 with 38k miles. Noticed the problem while on a road trip to New York a couple of weeks ago. Honda dealer near Ithaca, NY diagnosed the issue and determined that the temperature sensor needed replacing. ( Technical support at Honda concurred with the mechanic, and the part was replaced under the extended warranty.) The mechanic and shop owner observed fans cycling as normal before they closed up the bike. Once everything was back together the fans would not come on. The mechanic removed the seat again to re-check the relay. In doing so, he must have jostled the wiring harness leading to the relays, and the fans came on. We observed the fans cycle normally for 15-20 minutes. This lead us to believe there was a short in the wiring beyond the relay and before the ECM. Since the fans were "working" we continued on our trip to Niagara Falls, ON, and several days later back to North Carolina. The fans did not work in Niagara Falls, but were working normally when I checked after I got home. Two days later while riding locally, the fans did not work. So my experience has been fans work, fans don't work, fans work, fans don't work, and so forth.
My local Honda dealer has the bike currently. The mechanic is communicating with shop in NY and talking about replacing the ECM. :eek:4:I'm glad I bought the extended warranty (purchased through the board's sponsor).:lol: I might still have money left to be able to go to Wing Ding next month.
 

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Discussion Starter #17
Principale Let me know how your problem works out.

I was following the trouble shooting guide in the Honda tech manual and when I got through all the steps and all the tests were positive the guide said to replace the ECM. But looking at the manual it was clear that the temperature sensor and the circuit between it and the ECM had not been tested so I opted to test that part of the whole circuit. It's looking like I have a connection problem in the wiring/connector right now. I won't know until I get at the connector.

You may want to let your dealer know this. It is possible that he also followed the testing procedure in the Honda manual which in my opinion is incomplete.
 

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Discussion Starter #18
Today I took the gas tank out and removed the air box to get at C13. As it turned out I did not need to remove either one of them as I could not get at it after doing so. What I had to do was unbolt part of the brake system that was attached to the frame on the left forward side above the intake manifold. Actually having removed the tank and airbox probably helped as I could see down into where I wanted to go to get at C13. I probably would not have found it if I hadn't done this.

So I attempted to get the connector apart to clean it up and check the continuity again. So far I have not managed to get it apart because it is such a tight working spot. But having fiddled with it for awhile I decided to check the continuity anyway and guess what; I now have continuity. I'm guessing my fiddling with it caused the connector to make contact again. So tomorrow I'll take it apart, clean it up with some contact cleaner and check the continuity again. The sad part about all of this is that I have to put a whole bunch of stuff back together (airbox, gas tank, radiator etc) in order to test it again. So if it fails again after this it will be really frustrating.

It's not all bad though. I had intended to remove the gas tank to install a progressive spring and change the fluid on the pre-load adjuster. So I guess I'll do this while I have the tank out.

Stay tuned.
 

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How many wires?? I will go look at the manual.

I would find room, and in some way, wire past that connector and hard wire, solder and shrink wrap the wires.

That would be one thing I would not have to worry about.
 
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