Electric radiator fan question?

I have a fan harness kit from Ron Francis, am given the choice of wiring to the ignition switch and the fan shuts off when ignition is off or leave it hot all the time until sensor shuts off fan. Is this a matter of preference or is there an advantage to one or the other?

 

If ur switch goes ur fan might run ur battery dead.

 

What is a ur switch and a ur battery?

 

What if ur radiator in ur car works well enough that ur fan doesnt need to be in ur car?

 

Electric fans have a high current draw on start up. A relay in the system is a way to go. I'd use a temp sensor and a relay.

 

What is wrong with a mechanical fan?

 

The kit did come with a relay, there is no room for a mechanical fan, 8BA in an early chassis.

 

I wire all my cars with power off when ignition is off, no fan run on, if everything is working the way it should there is no need for the fan to run on. It can drain the battery enough to give you a hot start issue, ie. not enough juice to give a healthy cranking when you need it most.

 

x2...

 

that's the route to go.

 

I know this is an older post but does anyone have a diagram or can walk me through how to wire up the fan this way? I just picked up a 54 chevy that the guy had the elec fan all wired wrong and it was draining the battery and causing other issues. I would like to use the relay (the one i have is 40amp, with four posts 30, 85,86,and 87 , will that work?) and a temp switch. But i want it to be off when car is off..... Thanks for the help!