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Discussion Starter #1
How are you guys hooking up your fan? I am finishing up my electrical and am planning on using a thermostat to control the fan, but also have an override switch should the thermostat fail. I am starting to wonder if I am over thinking it and it is necessary, or better, for it to run constantly.

Any experience/advice is appreciated.
 

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Too Cheap to paint!
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My elec fan is on a sensor located by the thermostat housing. Turns off when the car cools below a certain temp. I usually kill the car with the battery cut-off, so that is my secondary fan "Off" switch.
 

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My cooling fan (relay) is controlled by the ECU. I can program both the turn on and turn off temps. I have it set to turn on at 190 and turn off at 180.

Sent from my Nexus 6P using Tapatalk
 

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Not a waxer
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Use the thermostatic switch; there is no need for the fan to run constantly. At highway speeds there is much more airflow over the radiator from the vehicle's movement than the fan can pull so running it would be redundant. Earlier versions of the Ron Francis harness had the fan relay on keyed power but the later ones have it hot all the time which means that the fan will continue to run after the car is shut off until the thermostatic switch reaches the "off" point (which can take 20-30 minutes). I don't like this and reconfigure them so that the fan circuit is on keyed power. As Jason mentioned I always put a manual override switch in parallel with the thermo switch just as a safety net---without it in the event of the automatic switch failing you have no means of turning the fan on to cool the engine in traffic.

Jeff
 

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FFCobra Craftsman
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Mine has a temp sensor in the intake manifold. It comes on at 195 off at 180. I view it as a backup for when I forget. I prefer to flip my switch on when I hit traffic and then the temp stays right at 180. I know 195 is not an actual problem, I'd just rather not see it.
 

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Discussion Starter #7
Thanks, guys. Sounds like I am not over thinking it by using the thermostat and an override switch.
 

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Snake Farmer
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I also have the over-ride switch, and the thermo switch. The over-ride switch is worth having, even if it's just for peace of mind..It's not that difficult to wire it in.
 

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I installed a 200 on / 185 off sensor in my 390 '66 Fairlane last spring. Last fall I changed to a 210 on and 195 because after I turned the motor off the 200/185 would keep the fan on for several minutes. Not ready a problem but I changed the sensor anyway. I have mine wired to cool after the ignition switch is turned off. I do have a override switch under the dash with a yellow LED light to tell me when the fan is running.
Sensor cost $10 to $35. I bought one online that was way off. Returned it for a refund. The two that I have used cost $10 each.
 

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Originally just had a thermo switch but after it failed once I put in an override switch. Thermo switch failed a second time so the switch is nice to have. On the road the car normally runs cooler than I would like with just the airflow so I didn't find out the switches had gone bad until stuck in traffic on a hot day. First time I had to pull over and jury rig a ground so the fan would run. Kind of embarrassing in the middle of downtown (not that these cars attract any attention). ;-)
 

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Same as most here. Thermo switch with an override. The fan comes on in stop and go traffic, but I dont think it runs much when moving. Engine temps stay pretty stable, and the FFR gauges are accurate enough that you can actually see the thermostat/fan cool it down. I flip on the fan every so often to make sure it works.
 
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