Good Switched Ignition Source for Electric Fan

[36 Dodge Brothers]

I am looking for a good switched ignition source for a electric fan controller that I am installing on my 68. I was recommended by a non Mopar owner to hook it up to the starter relay. I don't know if that makes sense so I am reaching out to my Charger owners brotherhood for some advice.

Regards,
Marco

[flyinlow]

I used a 30 amp in line fuse to power a relay near the fan. I took the power right from the charging post (trunk mounted battery) , but right from the battery would work. Put the fuse close to the battery.  The control circuit can be powered from an ignition or accessory feed. The starter relay terminal is hot all the time , so if you want to kill the fan with the ignition switch ,that would not work..

[b5blue]

  I recommend feeding the power for the fan right off the Alt. output, controlled with a rated relay for whatever amps the fan draws. Size the power wire properly and keep it as short as possible. You can feed the control circuit off the accessory line in your car to a thermal switch/on off switch as the relay draws very little power. Doing this keeps the draw of current on the supply side of the charging system and out of the alternator gauge, the regulator will still "see" the draw and function fine. As factory wired the car the battery is only for starting so any draw off the battery appears as a low battery and is fed through the gauge.
  If you have a stock charging system you may find a problem as idle output is low on them. I recommend upgrading the alt. before installing any large draw device, I installed a Denso 120 amp Alt. kit from Mancini and it works well. 

[Chryco Psycho]

I assume you are using a relay to switch them on & off , so you need to connect to the dark blue wire at the ballast resister or voltage reg .
the high power feed is good off the start relay or better off the back of the alt as suggested

[36 Dodge Brothers]

I want to thank you all for your advice . I got it to work, now it's time to fine tune it so it kicks in at the appropriate temperature.