There is a thermo switch behind the thermostat housing. Look in behind the upper front engine mount plate from the right side of the bike and you will see it there with a 2 wire plug in a rubber boot. It's kind of hard to reach, you will have to remove the right fairing lower. Pull the plug off the switch and jumper the 2 wires together and it should run with the switch on. If not check for power on the connector to the fan motor, access it from the left side.
Fan should come on when temp gauge is about half way in it's operating range. If it doesn't shut bike off, unplug connector at the thermo sensor not the fan. Jump the connector at the sensor plug & the fan should come on. ( Make sure the ignition switch is on when doing this). If the fan comes on in this fashion then its the thermo sensor switch.
Do a search on the site? Many ( me included) have used the 94 Geo switch as a replacement.
Sorry for not responding on the results. I took off the boot on the sensor, jumped the wires, turned on the ignition, and the fan came on! Apparently, the fan had not been working since I've had the bike (noise is fairly noticeable), but had only been riding it in colder weather which is why it probably never ran hot.
Since there is not very much wiggle room to take out the sensor, and I've heard horror stories on stripping bolts, I'm theorizing I will need to drain the coolant, take off the radiator and fan assembly, remove the seat so I can remove the covering containing the tool box tray, etc. The alternative would be to purchase a large enough socket to go over the sensor and take it out from the right side.
Okay, I will get the socket. I had already removed the horn out the way to get to the sensor boot. It seemed like there was enough room to slide a socket into the area besides the black brace that appears to be mounted to the engine.
After I drain the coolant, can I refill through the overflow tank, or do I have to take off the top cover (what looks like the gas tank - don't know real name) and fill through the fitting that has the radiator cap? And if I have to fill through the fitting, how do I take off the cover, etc?
Ya, you gotta use the rad cap as your port of entry. That top cover gets refered to as a false tank.
If you pull that off than there is even more things you can check while it's apart, Like your air filter. Some wings can be stubborn to burp the air back out of the system which can cause the wing to overheat.
I was just thinking. If you've never ran the bike when its warm or idled it long enough to get the bike really warm, how do you know the thermo switch is defective. Just a thought.
If you do go the Geo switch route, go to a local auto wrecker & get the sensor & wiring connector from a wrecked Geo of this vintage. From what I've seen the wiring from the bigger engine has the same plug end. Using the Geo wiring connector will make it much easier to put it into the wing's wiring. You just have to put to male plugs on the ends & they will plug into the old switch wiring. Cost me $5.00 but made the job simple.
When you get around to putting the antifreeze in, I would completely drain out the old and put in new. Fill to the top of the rad & keep filling until it stops taking antifreeze. Start the engine, the level will drop, add some more until the level stabilizes or starts coming up. Then put the rad cap back on & fill the overflow tank to the top mark. Run bike until top rad hose is warm/hot & the fan cycles on & off a couple of times. Shut down engine and as it cools it will draw fluid from the overflow. Next morning top up the overflow tank to the top mark. Keep an eye on the overflow tank for a couple of days to make sure there are no leaks.
The bike had been modified when I purchased it. The prior owner had taken off the instrument cluster among other things. I road it some without the instrument cluster and just a digital thermometer he had installed. I had a guy do some work on it and had him reinstall a some of the things that were taken off to include the instrument cluster. That's when I started noticing the temp climbing up. I've been lucky that I never rode for long or in traffic.
I will follow your suggestion and check with some salvage yards for the sensor and the wiring. Thanks.