I have an 04 Bruin. The oil cooler fan will not come on. I have jumped the fan at the relay and it comes on fine. I replaced my thermal switch. Still no fan. I jumped the two terminals on the CDI to duplicate thermos switch making and I can not get a ground signal to the cooling fan relay. Which I also tested and it is good. Ground should be coming from the CDI to make the circuit to fan relay. Since the other side of the realy coil is positive that should energize the fan relay. I also checked the ground to the CDI is good.
Does anyone have any idea what I may be missing before I go buy a new CDI? If so is their a good less expensive aftermarket unit for the Bruin 350.
Thanks in advance.

Not really wanting to hotwire or install a switch to run the fan manually.

 

I thought that was the purpose of the thermal switch, to turn the fan on and off when the ignition is on, I don't understand why that function would be wired into the CDI? are you sure you have the right wires identified? I am not familiar with the fan cooled oil cooler,but I would think it would be wired into a relay that is turned on and off by the thermal switch, not being controlled by the CDI. Do you have the wiring diagram to verify where the fan gets the power from? the fact that you jumper out the fan at the relay and it works fine may point to a bad switch,even new ones can be bad out of the box. But like I said, I have no experience with your wiring harness, I am just speaking from experience with coolant fans I have seen and worked on.
So are you saying the thermal switch feeds the CDI, which then turns on the relay? or does the switch feed the relay, and look for ground from the CDI?

 

I take it the oil high temp light is coming on but no fan. Send me a PM with your e-mail and I'll send you a copy of the service manual with a wiring diagram and some things to check before you spend a lot of money.

John

 

I have a sevice manual. But thanks. Yes the thermo switch feeds into the cdi. The cdi brings on the fan at a certain ohm resistance from the thermos switch. If the engine continues to get hotter the resistance from the thermo switch drops more and the cdi makes the circuit to the oil temp light. The thermo switch on a Bruin is more like a thermister than a switch. The cdi has three plugs on it. Most yamahas I have seen only have 2 plugs. One of the four wire plug deals soley with the oil cooler fan and light. Thanks

 

The fan is only a assist feature for the oil cooler. My 350 Yamaha Bid Bear has the same motor as the Briun and it did not even have a fan. I put 8000 miles on that motor.

I woud not even worry about it.

 

A new twist. Even though I may not need the fan like TLC said I figure its there, might as well use it. So I wired the fan relay hot off the ignition. The only thing between the relay and fan is the circuit breaker. It runs now but only for about 2 minutes then the fan cycles off for about 30 sec and comes back on. It will do this as long as the key is on. Here is the kicker unless the headlights are on, then it runs continous.
Thanks in Advance