Fan constantly runs on Maxim X

Looking for suggestions on fan that constantly runs on a XJ700. Any troubleshooting advice and cost of parts is greatly appreciated.
Thanks

 

I don't own a Maxim X and don't have much experience with them, but I do know there is a temperature sensor switch that kicks the fan on when the water temp rises. I bet that switch is shorted out.

 

Expanding on what BlueMaxim said, most cooling fan circuits comprise a fuse, a relay, and a temp sensor. Like BlueMaxim, I'm not familiar with the cooling fan circuit specifically, but in general, power runs through the fan relay coil and grounds through the temp sender. The temp sender usually closes at around 220F and opens at around 180F. When the sender closes, this completes the circuit for the relay's coil which pulls the contactors closed. When the contactors close, power flows to the cooling fan. When the water temp falls below a certain threshold (say 180F), the temp sender opens, interrupting the relay's coil circuit. The contactors spring back open and the fan ceases to spin.

With the bike started but cold, and the fan running when it shouldn't, unplug the wire going to the temp sender. If the fan quits running, the sender is shorted closed and needs to be replaced. However, if the fan doesn't stop, the relay's contactors are shorted closed. You would need to replace the fan relay instead.

 

As per Yamaha’s manual for Thermo Switch Inspection:

The electric fan is controlled by the thermo switch when the main switch is “ON”. Thus, under certain operation conditions, this fan may continue to run until the engine temperature has cooled down to about 98 C ( 208.4 F )

1. Remove the Thermo Switch
Caution: Handle the thermo switch very carefully. Never subject it to strong shock or allow it to be dropped. Should it be dropped, it must be replaced.

2. Inspect the Thermo Switch operation.
Thermo Switch inspection steps:
a. Immerse thermo switch in oil.
b. Check continuity as indicated temperatures. Note temperatures while heating the oil.

Test Step ---------- Oil Temperature ---------- Pocket Tester Rx1
1. -------------- 0~98 C ( 32 ~ 208.4 F ) ---------- Discontinuity

2. -------------- More than 105 +/- 3 C ---------- Continuity
-------------- ( 221.0 +/- 5.4 F )

3. -------------- 105 to 98 C ---------- Continuity
-------------- ( 221.0 ~ 208.4 F )

4. -------------- Less than 98 C ---------- Discontinuity
-------------- ( less than 208.4 F )

Test 1 & 2 Heat up tests
Test 3 & 4 Cool down tests

3. Install the Thermo Switch – torque to 23 Nm ( 2.3 m-kg, 27 ft-lb )



Looking at the electrical diagram the power for the fan circuit comes out of the rectifier/regulator on a red wire. The red wire branches into the main switch, and continues to a 10 amp “Fan” fuse. The red wire from the fuse continues on to a connector, after which it changes colour to a brown wire that ties to the Thermo Switch. The other wire from the Thermo Switch is a blue one that connects to the Fan Motor.

 

Nick, if I understand what you wrote correctly, you said there's no fan relay. In other words, the power to the fan is switched by the temp sender alone. That being the case, if a fan runs constantly, the only malfunction part possible would have to be the sender.

 

Gamuru, you understood me correctly, there is no relay on the circuit diagram shown on the XJCD for the XJ700/750 X series bikes.
The problem has to be in the thermo switch.
It sounds like it's a fragile part, wonder if it got banged about and quit working.

 

Thanks much for all the input on my fan issue. It is appreciated!