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Discussion Starter #1
I'd appreciate any help from the electical wizards out there. I'm planning to install a Spal fan with an adjustable thermostat on my '66 289. I'd like to wire it so that it stays on after I shut the motor off until it cools down enough for the thermostat to shut the fan off. Can I wire both the main fan power wire AND the relay fan wire to the battery side of the solenoid to accomplish this? The wiring diagram says the relay fan wire should go to a switched ignition wire so it is only on when the ignition is on. Also, the thermostat has it's own circuit breaker so I'm assuming this wiring should be safe. Is there another place I should go for the relay wire that will always have current?
Thanks for any help.
Tom
 

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Yes, both the power circuit and the trigger circuit could go directly to the battery, however may be a good idea to have a toggle switch in series with the trigger circuit.

I would recommend a circuit breaker or fuse in addition to the circuit breaker in the thermostat.

An adjustable timer relay would be a good idea "just in case"!
 

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I agree with the timer relay. Since the water pump won't be pumping it will take a really long time to get the coolant neat the sensor cool enough to turn off the fan. You don't want to always walk back to a car with a dead battery!
 

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Good responses. I have mine wired directly to the battery like Art suggested. And like whitelightning66 posted, on a hot day, or if the engine was particularily hot at shutdown, the fan will run quite a while after shut off to cool enough for the temp sensor to shut it off. Therefore, I have a three way switch under my dash so I can have the fan on(bypassing the temp sensor)...on with temp sensor... or off. If I'm leaving the car for more than a few minutes I shut the fan off. One advantage of having it run for a few minutes after shut off is that I never have a problem with percolating fuel in the carb. Fires right up without hesitation.
Dave
 

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Discussion Starter #5
Great idea on the timer. So would this have to be wired to a switched line somehow so that when the ignition was turned off, it would allow the circuit to be on for 5 minutes or whatever? Got any ideas on where to find that kind of relay? I got the thermostat relay through Jeg's, but I don't see a timed relay there.
Thanks again,
Tom
 

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Discussion Starter #6
One other note, I'm using a probe that goes in the radiator fins to drive the thermostat so I would assume it wouldn't take so long for the sensor to cool down. True?
 

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True. Mine is hooked up normal(turns off with the key off) I live in Florida and have never had a problem. Engine starts right up weather its been a minute or hour.
 

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Don't do it! A fan powerful enough to cool a V8 is going to be pulling close to 30 amps. Let that run for very long with the engine off, and it will drain your battery.

Ask me how I know :eek:. I used to have my fan hooked up that way. The second time I came out to a dead battery, I decided what a bad idea it was. Have the fan shut off when the engine shuts off.
 

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Discussion Starter #10
Different opinions are a good thing. :: It seems like a timer relay that would only allow the fan to run 5 minutes or so would solve the problem although I'm not sure where to find one other than buying one for a car that uses that type of relay.
 
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