Replace your Radiator Fan Fuse!!!

[YZF73]

Hey Everyone,

After participating in another thread concerning a failed radiator that had been jammed by debris, I decided to do some digging...

I thought it was a little strange that the fans were failing rather than their fuses blowing, so I checked the rating of the radiator fan fuse for the FZ6 and found it was 20A!!! To put this in perspective the rating for an '01 R6 is 7.5A, and 10A for a FZS1000.

I'm not going to accuse Yamaha of doing anything unscrupulous... instead I'll let you all come to your own conclusions. :thumbup:

Anyway, knowing this I decided to perform a test in order to find the minimum rating fuse that can be used for the fan circuit. Firstly, I fitted a 5A, which blew the instant the fan was switched on. Next I fitted a 7.5A, and after around 7-8 on/off cycles the fuse is still holding strong and doesn't seem to show any charring.

The fuse is located within the small fuse box behind the throttle side side pod.

From this, I can't yet confirm that a 7.5A fuse will last indefinitely (due to other variables that may increase the current demand of the fan motor). So, for now at least, I think it can be safely recommended that the fuse be replaced with one of a 10A rating, which is much more likely to protect the fan in the event that it become jammed.

Disclaimer: If you do decide to change your machines radiator fan fuse, please ensure that you monitor the operation of the fan and keep a keen eye on your engine temperature. Please treat the replacement as a test, providing yourself with the means to replace the fuse if it were to blow mid journey.

Over the next summer I'll monitor the operation of the fan on my bike, and report back as to whether the 7.5A fuse lasts.


Hopefully this may save someone some cash on a replacement fan. :rockon:

Yamahaboyz

 

[Botch]

Thanks for doing the experiment and posting your results. I had to replace my fan, and I always wondered why the fuse didn't save it; will change mine out this weekend! :thumbup:

 

[PhotoAl]

Wow! That is way too large for a radiator fan, they may have sized it large as most automotive type fuses are "fast blow" and an electric motor draws a substantial inrush current when it is turned on. Even so 20A seems high - and obviously is as it is not protecting the motors. Temperature is certainly a factor in how quickly the fuse blows, don't know how well the 7.5A fuse would hold up in the summer time. It may have been a design choice by Yamaha to let the motor fail instead of blowing a fuse and having overheating problems prematurely. A good experiment would be to measure the starting and running current and then block the fan motor and measure the current (but not for long). That would give a good indication of the size fuse needed. Typically a fuse can continuously pass 80% of it's rating. For example a 20A fuse would not blow with a 16A current but would blow at 17 or 18 amps, just take a while or might not if the outside temperature was cooler. Slow blow fuses are designed to blow slower and therefore not blow on motor starting current but should blow if the motor is stalled.

 

[YZF73]

Survived a Throttle Body Sync, so far so good.


Yamahaboyz

 

[Ssky0078]

Survived a Throttle Body Sync, so far so good.


Yamahaboyz

Did you do the throttle body sync yourself or did you take it to the shop? Have you used a Carbtune or did you make a homemade manometer?

I ordered a Carbtune finally and am going to do a TB sync this weekend.

 

[YZF73]

Did you do the throttle body sync yourself or did you take it to the shop? Have you used a Carbtune or did you make a homemade manometer?

I ordered a Carbtune finally and am going to do a TB sync this weekend.

I do all my own stunts. :thumbup::thumbup::thumbup:

I bought a Carbtune when my bike first needed a throttle body sync, figuring it was worth the money as I was putting in enough miles to need it around twice a year, plus it allowed us to perform sync's on the two other bikes in the household. Highly recommended, a brilliant piece of equipment and much more convenient than a liquid filled manometer.


Yamahaboyz

 

[Peter.C]

Thats some great info. I will put a 10 amp in mine when summer comes.

My fan and the 20A fuse blew last year on my summerholiday trip. A small stone had jammed the fan.

Standing in the south of france with a broken fan is not great when you are on a road trip.

 

[trepetti]

Hey Everyone,

After participating in another thread concerning a failed radiator that had been jammed by debris, I decided to do some digging...

I thought it was a little strange that the fans were failing rather than their fuses blowing, so I checked the rating of the radiator fan fuse for the FZ6 and found it was 20A!!! To put this in perspective the rating for an '01 R6 is 7.5A, and 10A for a FZS1000.

I'm not going to accuse Yamaha of doing anything unscrupulous... instead I'll let you all come to your own conclusions. :thumbup:

Anyway, knowing this I decided to perform a test in order to find the minimum rating fuse that can be used for the fan circuit. Firstly, I fitted a 5A, which blew the instant the fan was switched on. Next I fitted a 7.5A, and after around 7-8 on/off cycles the fuse is still holding strong and doesn't seem to show any charring.

The fuse is located within the small fuse box behind the throttle side side pod.

From this, I can't yet confirm that a 7.5A fuse will last indefinitely (due to other variables that may increase the current demand of the fan motor). So, for now at least, I think it can be safely recommended that the fuse be replaced with one of a 10A rating, which is much more likely to protect the fan in the event that it become jammed.

Disclaimer: If you do decide to change your machines radiator fan fuse, please ensure that you monitor the operation of the fan and keep a keen eye on your engine temperature. Please treat the replacement as a test, providing yourself with the means to replace the fuse if it were to blow mid journey.

Over the next summer I'll monitor the operation of the fan on my bike, and report back as to whether the 7.5A fuse lasts.


Hopefully this may save someone some cash on a replacement fan. :rockon:

Yamahaboyz

I read this thread and took the advice, replacing the fan fuse with a 7.5A. Well, yesterday I was stuck in a traffic jam on a hot day and the bike started to overheat, with the temp indicator flashing. Once I started moving it started to cool down and returned to normal. Checked the fuse this morning and the fuse had blown. I put in a 10A and ran the bike and all seemed ok. I let it heat up and the fan kicked on as expected.

I will leave the 10A in and see what happens.

If anyone has any further experience please step up and share.

Thanks

 

[FrozenBiker]

I will leave the 10A in and see what happens.

If anyone has any further experience please step up and share.

Thanks

10amp installed for the last month. Fan cycling has been fine so far.

 

[FinalImpact]

Great observation Yamaboyz! :thumbup: :thumbup: Not sure how i missed this thread. . . .

This is just me thinking out loud but when the fuse opens it potentially creates voltage drop across it. This potential could have a simple buzzer or light placed acrossed it (in parallel with the fuse). As long as the 10A fuse is is intact, the light or buzzer is never active. But should it open, it would sound alerting to its condition (I will try and verify this, relay could make it look like an open. Let me know if interested). This could be placed anywhere on the bike. A light would need to be routed for visibility. Of course you can do nothing and wait for the bike to overheat too. That is an option.

Out of pocket expense. About $6.00 A google search of 12V buzzers
12 Volt Buzzers | Buzzers Direct

 

[pookamatic]

I missed it as well - replacing it this weekend with a 10a.

 

[elus1ve]

Also missed this one. Going to replace mine with a 10amp.

Additional data on the 20amps, the 20amps fuse was fine last year when my fan got stuck and died. Proves that the 20amps is useless in this situation.

 

[GTPAddict]

Anyone know, or are able to find out, what the resistance of the cooling fan motor is? If I didn't have the lower fairing on mine I'd go measure it, but it's not real easy to get to with the fairing.

 

[FinalImpact]

Anyone know, or are able to find out, what the resistance of the cooling fan motor is? If I didn't have the lower fairing on mine I'd go measure it, but it's not real easy to get to with the fairing.

It is likely dependent on the position of the stator. I suspect its pretty low tho, like less than 5 ohms IF the commutator brushes are making contact completing the path. FWIW: its not in the manual.

This is:
Radiator fan motor relay
Model/manufacturer ACM33211M05/MATSU****A
Coil resistance 86.4–105.6 Ω

As an added kick, diagnostic mode 51 does this:

• Radiator fan motor relay Actuates the radiator fan motor relay for five cycles
• every five-second. (ON 2 seconds, OFF 3 seconds)
  
• Illuminates the engine trouble warning light.
  
• Check the operating sound of the Radiator fan motor relay five times.

 

[GTPAddict]

I would assume closer to 1 ohm. 5 ohms at 13 volts = 2.6 amps. If they have a 20 amp fuse, I would assume a nominal amperage draw of around 7-8 amps, with a startup draw closer to 12. That would bring the motor resistance somewhere around 1 - 1.5 ohms or so at 13 volts.

The reason I ask is this - if the motor resistance is closer to 2 ohms, you should be fine with a 10 amp fuse. But if it's 1 ohm I would not run less than a 15 amp fuse (or the 20 amp Yamaha saw fit to use). The OP said the R6 uses a 7.5 amp fuse for the cooling fan motor. That should put the motor closer to 5 ohms.

I'll see if I can run by the shop this weekend and grab my low amp probe. I can see what the fan is pulling at the relay since you described how to make the ECU turn the fan on. I'll let y'all know what I find out...

 

[FinalImpact]

But unlike a light bulb at temp, this has other properties, in-rush current, thermal changes from being ran, stall speeds and start-up current. A current meter in a cold environment would get a good baseline. Even grease when cool will increase the current load at start up. A clamp on one is an option too so you dont have to open the circuit. I have one so this is an option.

 

[GTPAddict]

Agreed, but it's a base line that we're looking for, correct?

As far as the clip on low amp probe, that's what I was going to use. I have these...

OTC Tools & Equipment 3820-13 Low Range Amp Probe with Display | StockWiseAuto

and

OTC 3820-06 Low Amp Probe

 

[GTPAddict]

Here ya go. I did a little testing tonight, see if this helps anyone out...

10 Amp should be ok, but close. Startup current draw on the motor (as I tested it on my bike about 2 hours after I got home) was about 8 1/2 amps (I saw as high as 8.7 amps one time) . Wait for the second cycle, that time you can see what the fan pulls when static.

I'd feel better with a 15 amp fuse, but a 10 will probably be OK. I just left mine alone (still has the 20 amp).

2006 Yamaha FZ6 Cooling Fan Current Draw - YouTube

 

[FinalImpact]

Eddie, did that have a min/max function to grab the peak load? Also did you intentionally stall the fan to get a peak?

I suspect you're right in that 10 is going to pop for many especially when cool out. Perhaps 12 to 15A would do the trick? I'll see if I can get/add some data this weekend. Thanks!

 

[GTPAddict]

I do not have a min/max function and I didn't bring my scope or DVOM home last night, so what you see is pretty much what you get. I ran the test 3 times in that video, in the beginning it had already started, so I did let the fan completely stop between tests to get a better start up current measurement. I was not able to get to the fan to hold it and measure current, but honestly I wouldn't have done that even if I could have.