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Electric fan thermo switch

Spanky

Spanky

Moderator
Staff member
Well, here we go again! :cool: The thermo switch for my electric cooling fan has failed once more. Out for a cruise yesterday, and in traffic, noticed the temp gauge registering above 200 degrees. Looked , and the fan blade in the electric fan was stationary. :mad: Used a jumper wire to ground the switch so the fan would run continually, solving the cooling issue, BUT . . . I just replaced the sucker last August!!! Cheap Chinese junk!:devilish: Now I know some of you are using the fan controllers with variable speed control, but I like the simplicity of the on/off thermo switch, which is fine when it works! Anybody know of a good domestic source for a thermo switch? Here's the one I'm using now purchased from Amazon. . .

thermo switch.jpg
 
All you hi tech guys. I’m still old school. I still have a conventional fan blade on the water pump and a v belt to drive it. It’s a stainless steel aftermarket unit. That’s about as cool as it gets for me.
 
On my roadster, I just have an off and on switch. On in town traffic, on off on the highway. Since I am a gauge watcher, it works okay for me.
 
I do not use a thermo switch. My fan is on all the time!
 
I know a number of people (me included) who use a Flex-A-Lite fan controller with a probe in the radiator. I think this is better than the time honored sensor into the water in the intake manifold or block. What happens when you have an air bubble or loose enough water that the level no longer reaches the sensor?
 
I'm using 180 degree off/on thermo switch, working for now, not sure of source.
In addition, have toggle switch wired so that fan can be turned on/off at any time below 180 degrees or if thermo switch fails.
Spanky said:
Looks like that's the way I'll go for now. o_O:rolleyes:
Click to expand...
 
Went cruising today in the fan-on-all-the-time mode - no issues (air temp = 84 degrees F). And because of my (a-hem) healthy sounding exhaust note, can't even hear the fan at the stop light! :D Only time you hear it is at start-up, along with the fuel pump.
 
The bad thing about running a toggle switch is forgetting to turn it on or off. I get the simplicity thing, but personally prefer some things to be systematic. A simple factory sender switch with a relay and diode works good.
 
I didn't use a diode on my alternator, so if I don't shut off the fan, my engine won't die. The fan will put power to the run system.
 
choppedtop said:
I didn't use a diode on my alternator, so if I don't shut off the fan, my engine won't die. The fan will put power to the run system.
Click to expand...
I too made that mistake on one. The fan will hold the relay in without a diode. For those who don’t know, a diode is basically a check valve for electric. It only allows current to flow in one direction. Inexpensive. Your voltage regulator in the alternator has them or your battery would discharge. You need another one installed in the relay circuit.
 
Thanks for all the input and suggestions. For now I'm just letting the fan run whenever the ignition is on. Maybe this Fall I'll consider some type of thermo switch. You guys rock! :thumbsup::D
 
Is your thermo switch the ground for the fan?

I use a relay to control the fan. The thermo switch grounds the relay triggering the on/off.
 
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