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Technical ELECTRIC FAN

Discussion in 'The Hokey Ass Message Board' started by CME1, Jun 26, 2022.

  1. CME1
    Joined: Aug 10, 2010
    Posts: 299

    CME1
    Member

    My 1942 Ford Deluxe 2Door has an electric radiator cooling fan installed. The hot wire from the fan goes to the ignition on off switch. So it is always on when the switch is on, there is no fuse in the line.
    My question is do I need a fuse in the line? I would also like to install a toggle switch to regulate the fan. I see no use for the fan to be on at driving speeds.
     
  2. Dustin 257
    Joined: Aug 20, 2021
    Posts: 280

    Dustin 257
    Member
    from Dallas

    Is the fan wire from the ignition switch going to a relay or is it the hot wire directly to the fan?

    painless makes a great fan relay set up that runs off of engine temp to turn it off an on.

    The ignition switch should be fused. So if the fan wire grounds it should pop the ignition fuse
     
  3. saltflats
    Joined: Aug 14, 2007
    Posts: 12,594

    saltflats
    Member
    from Missouri

    A fuse is always a good idea.
     
    Kevin Ardinger and Desoto291Hemi like this.
  4. Yes...you should use a fuse. The amps draw by the fan might be too high for the original Ford ignition switch......might burn it up. Most guys use a relay for an electric fan......recommended by many for low current switching. Also, temperature switches are available that install on the radiator core.....that way the fan goes on/off when the temp reaches your pre-set numbers.
     

  5. I grabbed the fan and wiring/relay out of a Pontiac Fee Aero. Worked great. Definitely use a relay.
     
  6. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 3,959

    Flathead Dave
    ALLIANCE MEMBER
    from So. Cal.

    Always use a fuse.
     
    jaracer likes this.
  7. Budget36
    Joined: Nov 29, 2014
    Posts: 13,174

    Budget36
    Member

    Changing my mind;)
     
  8. ronzmtrwrx
    Joined: Sep 9, 2008
    Posts: 1,137

    ronzmtrwrx
    Member

    Here’s a basic diagram of the (in my opinion) correct and safest way to wire up an electric fan
    34649DBD-D07C-409E-8610-547C9DF58FC8.jpeg
    You don’t necessarily have to run the wire from the toggle switch all the way back to the battery. A good chassis/body ground is sufficient to carry the low amp draw of the coil side of the relay. That is, as long as you have good grounds everywhere.
     
  9. CME1
    Joined: Aug 10, 2010
    Posts: 299

    CME1
    Member

    Thank all who replied . I will rewire with a fuse. I am going to look at adding a relay. I am also going to install a toggle switch to operate the on-off operation. Another thought is to move the hot wire to another location.
     
  10. 55blacktie
    Joined: Aug 21, 2020
    Posts: 793

    55blacktie

    Any accessory should be wired to the "accessory post," which should be the longest post on your starter switch. Any accessory that does not have its own on/off switch will come on automatically when the starter switch is in the On position. Any accessory that is wired to the starter switch should have a fuse. For instance, Newport recommends a 6 amp fuse for their electric wipers; unfortunately, it's not included in the kit.
     
  11. fastcar1953
    Joined: Oct 23, 2009
    Posts: 3,567

    fastcar1953
    Member

    Was electric fans around in 65? just asking
     
    Desoto291Hemi likes this.
  12. 55blacktie
    Joined: Aug 21, 2020
    Posts: 793

    55blacktie

    I don't recall seeing them until the 90s.
     
  13. Wiring it the way you intend will also result in a run on condition if the toggle is closed when you turn the key to the off position, the fan motor will become a generator and back feed into your ignition coil letting the engine stay running until the fan spins down. Do it correctly with a relay like the previously posted schematic shows.
     
  14. Mr48chev
    Joined: Dec 28, 2007
    Posts: 33,861

    Mr48chev
    ALLIANCE MEMBER

    The relay is a good idea if the only change you make is installing a relay that is triggered by the ignition switch and put a fuse in the power line from the power supply point to the relay.
     
  15. BamaMav
    Joined: Jun 19, 2011
    Posts: 6,711

    BamaMav
    Member
    from Berry, AL

    Toggle switch is good as long as you remember to use it. Better way is with a temp sensor wired through a relay, and if you want, a toggle switch override to manually turn on the fan. That way, it will work automatically, and if you need to cool it down without the engine running you can also do that.
     
    Cosmo49 likes this.
  16. 57Fury440
    Joined: Nov 2, 2020
    Posts: 253

    57Fury440
    Member

    Electric fans have been around for a long time. A friend had one on his 1964 Sport Fury with the 426 wedge back around 1965.
     
  17. Joe H
    Joined: Feb 10, 2008
    Posts: 1,525

    Joe H
    Member

    If you have a big fan, use big wire to power it. 10-12 gauge wire right off a 50 amp fuse and relay. The fan will last longer and run cooler and faster with the heavy wire. Also, be sure the relay is heavy duty 40 - 50 amp rated one.
     

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