Help - Radiator fan does not work - overheating!!

[pretendertothecrown]

Hi everyone,

Can anyone help? I've owned my Fazer 1000 for around 4 years. I tend to run it at low revs in high gears. I've only known the radiator fan to kick on once or twice and that's even after the temp light has come on. Recently the seal failed on the water pump and I had it replaced but the fan did not come on when they tested the cooling system. Can anyone give me some idea of a systematic check I can do in order to eliminate possible reasons for this? I know that the fan has not got any debris in it as the fan spins freely. it could be a relay problem or a thermo problem but I have no idea how to check this as I have no experience with the electrics.

Can anyone help me?

[celticbiker]

What year bike is it? (doesn't display on the mobile)

[Falcon 269]

Who did the pump seal replacement?  If they felt the fan wasn't working, they should have found out why before handing the bike back to you, I'd have thought.

Anyway, start with checking the fuse.  If that's fine, apply 12v direct to the fan via the connector which you'll find if you trace the wires back from the rad.  It might be that the connector itself could be the issue. 

If those come up blank, move on to testing the thermostat switch and the relay behind the left side panel.  I think there's a workshop manual download available somewhere on the forum which will give you the full fault-finding process for the bike.

[pretendertothecrown]

Sorry guys. The model is a 2002 FZS1000 fazer.


The garage changed the pump seal,.they didn't know why the fan wasn't working after that so I thought it best to take it away and try and resolve this on my own without it costing me an arm and leg.


I will check the fan relay and let you know. Many thanks gents

[pretendertothecrown]

I haven't managed to do all the checks yet, but on first inspection found out that the radiator fan fuse was burnt out    so replaced it yesterday on the way home from work.


The fan still didn't start up though. I'm getting a multimeter this weekend and will check the relays and hook up a battery to the fan to see if it still works as there is no debris to stop it spinning.


Also, I read somewhere online that HID lights are problematic for the radiator fan circuit - something to do with the ballast charging up causes a power surge that will burn out the radiator fuse. Has anyone else had problems with this?

[Falcon 269]

Good luck with the testing.

Not impressed that the garage who did the pump seal repair didn't even check the fan fuse, though ... wouldn't be using them again, if it were my bike.

[pretendertothecrown]

I wasn't impressed either to be honest. It was in the garage for a week, and if the fan wasn't working I would have thought they would have at least Googled the problem to find a solution if they didn't know.


I figured as long as I had the bike back, I could run it at low revs even in the heat and it shouldn't be too much of problem until I get my multimeter and check the relays.


I did check the fan fuse today when I got home from work and it's still in tact. That said it does not come on when I start it up like it should - mind you I don't remember the last time it did.


I'll keep you guys posted over the weekend and thanks again.

[PaulSmith]

I haven't managed to do all the checks yet, but on first inspection found out that the radiator fan fuse was burnt out    so replaced it yesterday on the way home from work.


The fan still didn't start up though. I'm getting a multimeter this weekend and will check the relays and hook up a battery to the fan to see if it still works as there is no debris to stop it spinning.


Also, I read somewhere online that HID lights are problematic for the radiator fan circuit - something to do with the ballast charging up causes a power surge that will burn out the radiator fuse. Has anyone else had problems with this?

Have you tried going faster?

More seriously, I don't know what you read or where, but why the foc would the headlights (HID or otherwise) have anything to do with the fan circuit?

[pretendertothecrown]

Admittedly Paul, I don't have enough knowledge about electrics but I will be check relays this weekend.


Good news though -when I got home from work and parked up in neutral, the fan was on. Looks like all that was wrong was the fuse and I can't understand why it would take so long to diagnose at the garage.


Thanks again gents

[5LV]

Rad fan should kick in with the bike on the stand after it has been running for 2 or 3 minutes.
Check to see if the fan turns freely by hand (with the ignition off)
Yes, then run a live (or could be an earth) to the motor feed to see if it spins up
No, sort out fan
HTH