cooling fan not working

[firefighter1c57]

Ok, it's a 04 XB12R. Buell race exhaust, ECM and K&N, breather reroute.

Thursday, the GF and I rode across town to eat, about a 20 minute ride. Outside air temps here are about 104* with a heat index of 110*. When we parked at the Bar B Q place, I noticed the fan didn't turn on. I mentioned to the GF "that doesn't seem right". Hour or so later, we leave. Bike will not idle, IE, needs constant throttle input to stay running. We head home. Jump on the highway and again, about a 20 minute ride. Pull bike in the garage which is about 120*. Still no fan. Yesterday, pulled it apart. Temp sensor has a resistance of 24,000ish at room temp. Start up, and resistance drops as it should per the manual. Voltage of battery is 12.5ish running, 11.5ish not running.

Now, here's where it gets weird. Jumping from the battery to the fan makes the fan run. The connection to the fan has the same voltage as the battery once the resistance in the temp sensor drops below 19,000ish. So, 12.5ish volts at the plug engine running, 11.5 volts engine off/key on, but, no fan run...

 

[Livers]

Did you check the fuse? Yeah it sounds weird, but ...

 

[anrkizm95]

check the ground side of the connector it most likely not getting a ground signal from the ecm.the head temp sensor send a signal to the ecm then the ecm supplys the ground to the fan.also the race ecm commands fan on at speeds over 15 mph.if your not getting a ground from the ecm check the head temp resistance at the ecm connector by back probing it. this will let you know if the ecm is getting the data fron the head temp sensor.

 

[firefighter1c57]

I'm sorry, yes, the fuse is good. anrkizm, are you saying that the fan is ground switched?? I do know that at room temp, the fan connection doesn't have voltage, once the head temp sensor passes 19,000ish ohms, the fan wire has voltage. I did not check any grounds though, I was using the ground strap on the back of the engine for all my voltage checks. Could be a bad ground on the fan connection circuit.

 

[anrkizm95]

anrkizm, are you saying that the fan is ground switched??

yes well i have manuals for 07,08,09 and 10 the wiring diagrams show positive side of fan is fused and is powered up when ign is on.ground side is supplied by ecm.wire colors are yellow/brown on pos side black and orange on ground side.

just looked at the online manual for an 03 xb9 and it shows pos side is fused and ground side is ecm controlled

 

[firefighter1c57]

that would make some since. The ECM would have two different circuit's for ground, one resisted to control the fan high/low speed settings. I hadn't looked at the wiring diagram.

Yea, I have a 04 for manual for a Lightening, and the 05 manual on PDF. I guess I should pay a bit more attention to them.

Now, since I'm looking at both a fan no run in high and low, I guess I need to check continuity in that black orange wire. Uhg, I didn't want to rip the front of the bike apart too to get to the ECM but I guess I am.

 

[Iamarchangel]

Fan doesn't always come on when you expect it. I've noticed that sometimes when I've just gone through some extremely slow traffic, the fan does not come on.

I figure it has just finished its cooling cycle when I've stopped.

Does that fit?

 

[anrkizm95]

these might help you

 

[firefighter1c57]

Ok, next step. I unplugged the temp sensor and jumped the wire from the computer strait to ground. IE giving it a zero resistance. This should make the computer think head temp of 572*F. Testing the black orange wire from the fan to ground still no continuity.

So, either the black/orange wire is broken, I have no connection at terminal 6, I have no connection at terminal 2 and 11, or my computer ground is bad.

Thru all this, I've still yet to get a code unless I had something unplugged while I was running the bike doing test.

 

[firefighter1c57]

Did some more testing last night. It seems to be a ECM problem. Going to ground from the ECM with the pink and yellow wire, IE indicating a temp over 572* to the ECM, the fan will come on and run for about 5 to 10 seconds then shut off. Is the Race ECM programmable/check-able with ECM spy and cable?? I've been told it is locked, and I've been told it's not.

 

[jimijeans]

I would hook the ECM Spy up to it and see if it will work .Sometimes the Spy program does work on Race ECMs.Possible frame ground from Ecm to chassis. Could trace the ECMs ground wire pig tail Properly into it up close to ECM and put an extra ground off that to the chassis and see what happens. Just a thought. Man I hate that kind of work I have spent whole days chasing down that kind of problem. Patience will pay off on this. *Jimi

 

[firefighter1c57]

Thanks Jimi. I checked both grounds coming out of the ECM(high speed and low speed). Both are good. Resistance check through the ECM from pin 6 to both grounds are good. I'm pretty much convinced now that my engine temp sensor, though showing resistance and dropping in resistance is out of specifications per the manual.

That said, it's just been to "F"ing hot to do anything else with it to see.

 

[firefighter1c57]

Got it fixed. It was indeed the temp sensor. It was showing correct resistance at room temp, and resistance was dropping with engine running, it just didn't seem to be dropping fast enough. Replaced it and fan works.

 

[ATFIII]

Glad you got it fixed!

 

[saucyjoe]

old thread i know... but +1 for check fuse....