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.
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
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.
Here’s a basic diagram of the (in my opinion) correct and safest way to wire up an electric fan 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.
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.
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.
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.
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.
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.
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.
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.