MIKE'S FANS

    I have just rewired my two interior fans in our Track Tvan so they can run fast or slow together. You just need a two position switch with 6 terminals on the back.

    I have also put a separate switch on each fan holder so they can run independently when in fast mode. By definition, because the wiring in slow mode is using one fan to provide the resistance to slow both fans, then both fans have to be on in this mode.

    I did look at an adjustable 6-28V DC to 3-15V DC converter on sale at Jaycar for about $25 that would achieve the same objective and allow fans to run on 6V, 9V, or 12V and just one fan in slow mode but I decided to keep it simple. The 6 terminal switch cost $3.

    Assuming you are looking at the terminals from the back

    When the switch is in the up position 1 & 3 connected : 2 & 4 connected the fans run fast and can be further switched on the positive wire so that only one is in use if required.

    When the switch is in the down position  3 & 5 connected : 4 & 6 connected the fans run slow.

   

    I used the 120mm square 12V computer fans and they are really effective and comparatively quiet drawing only 0.38 amps each in fast mode. Jaycar Cat. No.  YX-2518

    In comparison the smaller 80mm fans  Jaycar Cat. No. YX-2513  (which I normally get from old computers discarded on kerbside clean-ups)

I used a switch Jaycar Cat. No.  ST-0576 $3.75 for the speed control.

The DC converter I mentioned is Jaycar Cat. No. AA-0218  for $24.95

 Thanks to Mike Sargeant for sharing this idea with us