[6pack] DPDT on-off-on rocker switch for electric fan conversion

[Foster, Stan]

Just wanted to follow up on my fan override switch question. Many thanks to
everyone that responded both on and off list. I got not just suggestions but
circuit diagrams (Michael Porter), and detailed installation guide with part
numbers (Richard Seaton).

I did some initial tests with off the shelf auto parts store illuminated
rocker switches. That failed miserably because the switches were cheap junk
that fell apart (the connector tabs pulled out of the switch body when I tried
to remove the spade connector) and because internally they are not suitable
for what I was trying to do because in the off position the active part of the
SPST switch is parked across the other two contacts and creates a short if you
try and connect it up different from the published instructions (I was trying
to switch ground and still illuminate the lamp with 12v).

In the end I found a better made SPST switch at Radio Shack which came with a
robust mounting bracket that I drilled to accept a miniature 12v LED and made
my own illuminated switch. This switch switches ground to the fan relay to
force the fan on and the LED is powered from the same relay via the fan power
feed terminal. Since I had the engine bay dismantled anyway I incorporated all
of the wiring into the loom so the installation looks very clean under the
bonnet. The switch is not yet installed but will be mounted to the metal lip
under the dash using a home-made adapter to move the switch back a little and
adjust the angle.

Pictures here:

http://s38.photobucket.com/albums/e119/foster461/Fan%20installation/

Stan