Fan Will Not Run - 1985 Yamaha XJ 700 X Maxim

There are several reasons why a Maxim-X fan might not run. One reason might be that the fan fuse has blown. The fan has a 10A fuse all its own which is located under the cover for the indicator lights by the ignition keyhole (there are four #2 Philips screws that need to be removed before the cover can be removed to access fuses and indicator bulbs).

If the fuse is OK, then the next possibility is that the 'Thermo Switch" which trips the fan isn't making a connection. The Thermo Switch is threaded into the thermostat housing and has a push-on wire connection. Actually, the temperature sensor is also threaded into the thermostat housing but it is the smaller of the two sensors/switches. The larger of the two, which I believe is accessible from the left side of the thermostat housing, is the switch that trips the fan. Often the push-on connection gets oxidized and needs cleaning. Often the wire connection becomes loose and can simply be tightened and pressed securely back into place to restore the connection.

Another reason the fan might not spin is that the power connector has a bad connection. From toward the right side of the fan you'll see a short length of wire (maybe a foot) with two conductors leading to what I seem to recall is a red plug. Like all the other plugs, that can oxidize and create a bad connection. The plug can also come loose if someone before you has broken the locking tab or maybe didn't plug the two halves properly together again. You'll find the plug end up around the right side of the thermostat housing.... between the thermostat housing and the right frame rail. That's also where one white and one yellow plug are tucked away (the yellow is the power plug for the left coil and the white is the power plug for the right coil). It's a pretty tight cluster of wires and plugs but finding the red one for the radiator fan power is fairly easy because tracing the wire back to the fan is fairly easy.

So, if the fuse is OK and the thermo switch is working, and the connection from the thermo switch is a good one, and the power connection for the fan is solid.... then the fan might be burnt out. If so, they come up on eBay often enough so it shouldn't be too difficult to find a replacement.

But, from my experience, my money is on the fuse first, the bad thermo switch connection second and possibly a failed thermo switch third. That's what I've seen most often. Whatever it is, it's a reasonably easy fix.

Have you checked the thermal switch for the fan. (fitted on the rad) ? or check on a battery and checked the fan for movement..