cooling fan issue ... HELP

[sallydog]

Fan doesnt come on, when i jump it out the fan works, i tried 2 fans. the fan fuse is good. when i checked the dealer they found a thermo senser in the loop somewhere but didnt know where it was. i dont think that is the problem because my gauge show air and motor temps. is there a relay to turn the fan on at a certain temp? and where is the relay or senser?

TIA

 

[HeliMark]

Here is the location of the sensor (#6) on the bike. I think I heard someone say the ECM is the one to trigger the fan, but could be wrong. Guess I would disconnect the line to it and using a meter, see if it does anything as it warms up.

http://www.yamahapartsnation.com/oemparts/a/yam/5085c762f8700223282354cb/electrical-1

Mark

 

[Sierra1]

My fan doesn't come on unless it's hot & I'm stuck in stop/go traffic. I think that my fan has only come on twice since I bought the bike; and that's here in Texas.

 

[tpak]

I don't think it comes on until the temps reach 218 or 220F - if I let it idle in the garage it takes about 8-10 minutes to get it up to those temps and then the fan kicks on. That is with summertime temps in the garage of about 75-85F. Then it sounds like a friggin leaf blower is going. The downside is that it blows hot air on your left leg and that can be un-fun in the summer heat and stop and go traffic.

 

[sallydog]

mine used to come on. now it gets to 240 and then the red lights come on but no fan. i looked at that schematic but it is very vague as to where it is. i have to burn off a full tank of gas before i can remove the tank to look more. is it possible the relay is built into the senser? like i said, my temp gauge still works. my bike is 2012

 

[HeliMark]

I was just thinking, pretty sure the ecm controls the fan. ACV when he does a reflash, changes the temp when the fan comes on. Doubt there is a separate wire from the sensor to the temp display, so that would mean the ecm is getting info. Unless part of the ecm went bad, it has to be a wire from the ecm to the fan. Maybe find that wire and bypass it from the ecm and see. Or do a continuity check on it.

Mark

Sent from my SM-G930U using Tapatalk

 

[tomatocity]

Fan On 221F
Fan Off 212F

Been hot in Sacramento lately. I normally let the fan cycle off before shutting down the engine. The other day it cooled to 213F and wouldn't cool any more. 2015 ES.

How long did you let it run at 240F.

 

[sallydog]

i shut it down as soon as it hit. been riding without a fan 2 weeks. i need to get this figured out

 

[steve68steve]

Ok, manual page 6-4, "thermostat". There's a diagram which shows the thermostat sitting in a housing with 3 bolts. The housing looks like it's sitting between the two air intakes under the airbox. Follow the upper hose from the radiator, it ends at the thermostat housing. Somewhere right next to the thermostat housing is the coolant temp sensor. It looks like bolts directly into the block. It's one of those funky proprietary multi-pin connectors - it will have a wiring harness coming off it which leads (eventually) to the ECU. There's a crush washer under it and a torque setting (I'm away from manual at the moment, typing this from memory).


The service manual has pretty detailed instructions for testing the thermostat and the radiator cap, but I don't see anything for testing the coolant temp sensor.


It sounds like you've confirmed that your fan turns on when it gets 12V, but it won't turn on when the bike temp is north of 221F. I assume you're reading the temp from the instrument cluster display... which probably gets it's info from the sensor. So, if it's giving you a changing reading that makes sense on the display, I'd be more suspicious of whatever wiring is between the sensor and the fan. Is there a relay or something which could be bad, or a chafed wire? There must be some switch, unless it's all handled by the ECU, which would be worst-case. Switches, relays, and wiring point-to-point would be straightforward to test.

You can see the radiator hose terminate at the block in the linked diagram. The thermostat is item #1. What I'm calling the "thermostat housing" is actually item #2, "thermostat cover". The view on p6-4 in the manual which shows the coolant temp sensor doesn't seem to be on Partsfish, but it's shown (exploded, so hard to tell) just to the right of the thermostat cover.
http://www.partsfish.com/oemparts/a/yam/53306fe8f870024560f03e49/radiator-hose


HTH. I'm watching this with interest because I've been hard on my cooling system and a failure wouldn't surprise me.

 

[RonH]

To expand on Steve's good advice in the last post, the way the fan works is one connection is at ground all the time, the other connection to supply power goes to a relay and when the relay is turned "on" the other connection of the relay is supplied power from 12v through the fuse, so the chain is 12v to fuse, through fuse, through relay to fan motor. The relay coil connections to turn it off or on is wired where 12v is always on one connection, the other connection is drawn to ground via the PCM to energize the relay. The coolant temp sensor is a temperature sensitive resistor that changes resistance with temperature change and is wired into the PCM.
So the basic way the sytem works is temp sensor sends a voltage to PCM, PCM uses this info to turn on fan at 221 degrees by grounding the relay, while the other connection is 12v, relay turns on. 12v is supplied to fan fuse, through fuse, through relay to fan, other connection of fan is always grounded so fan runs. When temp drops to 212, the PCM removes the ground from the relay, the relay turns off, fan turns off.
If the display is correct in reading temperature, as Steve said, the sensor appears to be working, and the problem would be most likely the relay or associated wiring.
Good Luck

 

[2daMax]

https://www.manualslib.com/manual/825471/Yamaha-Xt1200z-Z-2010.html?page=615#manual

Item 91 is a fan Relay. So yes, there is a fan relay and is connected to the ECU. (Far left, 2nd item from bottom)

Legend for numbered designators.
https://www.manualslib.com/manual/825471/Yamaha-Xt1200z-Z-2010.html?page=612

I believe it is located on the right side of the bike in the battery compartment. Check the wiring color to locate which is the relay.

 

[steve68steve]

I would definitely look at the voltage coming into and out of that relay at temp before taking anything apart.

Sent from my SCH-I545 using Tapatalk

 

[Checkswrecks]

Sorry to not respond sooner, but didn't have the maintenance manual handy. Work can SO get in the way.




The coolant/fan temp sensor (wire diagram item 90) is just an on/off switch and is NOT the temp you see on the dash. That is air temp from the sensor at the air box. Now that you know where the coolant/fan temp sensor is, turn on power and:


1. Ground the blue wire which goes from the relay (item 91) to the temp sensor. This will mimic a hot enough temp to turn the fan on. If it comes on, your temp sensor is bad. If not . . .


2. Check for battery volts at the blue wire to the temp sensor. This is coming from the relay.
3. If no voltage in step 2, check for it at the downside of the relay.
4. If none in step 3, check for power which should go to the relay at the fuse (item 16).
5. If all appears OK, jump the relay heavier wires and the fan should come on. If not, you have a wire problem between the relay and the fan.
6. If not, check for power on the upside of the relay power to the fan. If you have power there then the relay contacts are not closing and the relay is bad.

That's pretty much the circuit. If you want to "shotgun, replace the fuse, relay, and temp sensor. You have enough miles and they are cheap enough that it can't hurt.


If you don't have a test light or multimeter and the fan didn't come on when jumping the blue wire to ground, swap the relay with the one for the aux lights (item 15) and go for a ride. If the fan comes on the relay is bad. If not, it's probably a temp sensor with lesser odds of being possibly a wire issue.

 

[sallydog]

THANKS for all the info and help. that should be what i needed to solve my problem. i might not get to this till next week but i will let you know what happens

 

[RonH]

Looks like different year manuals use different numbers to designate items. In my 2012 manual item 100 is the fan, iem 99 is the relay, item 34 is the coolant sensor. I don't see any other things like a coolant switch. Be careful grounding anything unless you are sure you know the circuit. According to the 2012 manual I'm looking at, the green/yellow wire to the relay is the wire from the PCM that when grounded would turn on the relay and fan.

 

[Checkswrecks]

True. Fortunately, this circuit is so simple you can just follow wires.