[vettestr]

Hello Myles and Bill,
Myles the coil is redundant by design. The current draw of the coil in the relay is negligable but does allow the real current draw through a relay designed to handle the demands of 1 or 2 fans. The typical demand of 2 fans is in range of 15 to 25 ++amps and this is too much amperage for an ignition switch alone unless a special rated one for fans but why push it ? Relays are cheap and are designed to pass high current so just the right wat to go in my opinion. I do insist on soldered connections and often put a dab of RTV on nut holding wires so vibration not a factor.
If you forget to turn on a fan switch you can harm motorso redundant is ideal in this case. You may also want to turn on before temp sw for some reason so toggle is just nice to have.