2007 CBR 600rr

Having an issue with my fan relay getting burnt out and causing the bike to overheat.

For about a week I noticed the fan wouldn't kick on when it's supposed to, 219-220ish F. Troubleshooted a bit via these forums and stuff, basically came out to be 1 of 5 things.

Fan motor broken
Bad Relay
Bad Thermostat
Bad Temperature Sensor
Bad ground/loose connection somewhere

Well, replaced the relay yesterday and the bike seemed to run perfectly fine, fan would kick on at stoplights around 220 and the bike would run at a stable temp (170 - 175ish) while riding down the highway. Aaaand it seems to have burnt out again after going for another ride.

The fact that everything else seemed to work otherwise tells me I have a bad wire connection somewhere. The temperature gauge on the cluster will jump significantly between temperatures, ie it'll go from 194 to 205 in an instant, then back down to like 198 or something whereas before it was a steady incremental climb up or down, etc.

So basically.. what wires should I be looking at? I have a Scorpio alarm system on it and an aftermarket undertail brake light/turn signal combo, has always worked great with no issues.

Aftermarket front turn signals which have been TWISTED together but I'm going to actually solder them up and see if that helps. But just so I don't keep blowing out relays, what else should I be looking at? Where are all the grounds located?

Thanks much!

 

The Fan Motor Relay is controlled by the ECM. Not sure why they made it so complicated. What was your indication that the relay was actually bad?

 

Well, the fan wouldn't kick on when it was supposed to (220ish) and my dad always taught me to start with the cheapest thing first when troubleshooting. And it turns out it's the relay causing it not to turn on but now I'm not sure what keeps killing the relay itself. Any ideas? Is it the fan drawing too much power? I can't imagine that would cause the relay to burn up though.

 

If the fan draws too much power, then the fuse protecting it would blow. For the fan to turn on, the relay has to be told to turn on. Is the relay being told to turn on? You can only answer that with a meter and wiring diagram so you know what wires to check.

 

I have a multimeter, though not exactly sure what I'm looking for. A power draw over 20amps when it hits 220 farenheit? The fan itself spins quite smoothly, no real resistance so I'm assuming the bearings aren't shot causing an overdraw but not excluding that possiblity entirely just yet.

It's also suspicious that the temperature gauge is somewhat erradic, jumping 8 - 10 degrees (give or take) in either direction. Granted it does go down when I'm moving but nothing but up at stoplights, though still in significant increments.

What should I be looking for when testing the fan? Or am I testing the relay?

Thanks for the help once again, I do believe it was you who essentially me through the valve check posts recently and the bike was running flawlessly up until now

 

The relay and what is controlling it is most likely the issue. The relay is going to have 4 wires going to it. 2 of them are controlling the power going to the fan. The other 2 are what switch the relay on and off. The ECM tells the relay to turn on and off. The ECM takes temperature information from the ECT (Engine Coolant Temperature) sensor so it knows how hot or cold the engine is. There is a procedure in the manual on how to test it's operation with a meter. Having a bad connection on that sensor could produce the symptoms you are getting, with the temp jumping all over the place, so worth a look. If the ECM gets bad readings, it won't control the relay and fan correctly.

Do you have a shop manual? If not, here is one on ebay for a reasonable price. If you don't have one, consider it an investment in you knowledge.
https://www.ebay.com/itm/20384495924...EAAOSwzn5iGi3Y

 

Well, I took out the relay and tested it (hooked it directly to another 12v battery) and can hear the contacts connect when power's applied -- this is true for both the 15+ year old one and the new one, so I don't think the relay is actually getting burnt out. Weird how the new one worked perfectly fine for the first hour or so after I replaced it though.

Anyway.

I'm going to attempt to replace the temperature sensor from the right side of the bike -- it seems I can ACTUALLY get to it without having to take off the tank/intake, etc. Tight, but think I'll be able to manage. The way it's jumping between temperature readings is making me think it's faulty after so many years.

Will the coolant pour out once I remove the sensor to replace it? Or is it somehow blocked? I'm not sure where it actually sits in the engine, etc.

 

The sensor is not that old and rarely go bad. Fluid will probably want to come out so maybe have someone on hand that you can plug the hole with until you either put a new one it, or test if the old one is actually bad or not. The manual has the procedure on how to test the sensor and determine if it's good or not. Good luck.