Those that have been following the DOG Aviation blog know installing
panel mounted switches for the fuel pump and left landing light has been in the
works. Wanted to have nice labels made for the switches as opposed to using a
Dymo style stick-on label. Decided to use the same style of label material Pete
used in his gorgeous RV-9A (www.myrv9.com)
which is a two color layered plastic .020 thick that when engraved exposes the
color below …. flat black with white underneath was chosen.
The goal was to have the engraver cut the rectangular slots for the
panel switches into the label material so the two switches could be installed onto
it. This required the need to create a scaled detailed drawing for the engraver,
but I did not have software in the new home computer I trusted to get the
scaling correct. Mike K.’s wife Kim came to my aid and helped me create a
scaled drawing using her sewing machine software …. yep, that is right, sewing
machine software. Once I had a scaled drawing to work from that had the correct
switch positioning and scaling, I was able to modify it for engraver. Thanks to Kim, I was able to obtain the
correct scaling for the switches.
One of the down sides of the sewing software is that lines are thick
because they represent stiches, but that was easy to fix using picture editing
software at home. Once the drawing was converted to a single line a font was
chosen that is a close match to the font on the ignition switch module. This
was taken to the engraver who understood what I was trying to achieve and did
an outstanding job of creating the label for the two panel switches. A special
thanks to the employees of Engravers Edge for creating exactly what I was
The label for the two panel mounted switches that will be installed
above the ignition switch module.
Even though the bezel on the two switches will keep the label in place,
the decision was made to place a really sticky tape on the backside of the
label … so the label needed to be installed correctly the first attempt. To aid
in the alignment of the label while sticking it in place onto the instrument
panel, the two switches were inserted from the back side of the panel so they
could be used as alignment guides. Because the plastic for the label is a two color
plastic the sides show as white so a black permanent marker was rubbed along
the edges to blacken them prior to installing the label onto the instrument
The two switches were inserted from behind the panel and used as an
alignment guide for positioning the engraved label.
Fuel pump and left landing light switches installed along with the
For those fellow builders that are interested in the switches being used,
they are the same type used by Van’s in the Fuse and Switch module. The switches
are manufactured by Otto and are from the K1 series. Otto manufactures a plethora
of switches in this series with long part numbers and each letter in the number
means something like momentary on, or steady on, terminal style, LED or no LED,
LED voltage rating, color of LED lens, etc. The part number for the Otto switch
in the K1 series that has off to steady on operation, with a 12 volt LED and
green lens is: K1ABAPCABA.
The Otto K1ABAPCABA rocker switch is from the same family as the
switches Van’s uses in the Fuse & Switch module.
Below is a diagram I made of the back of the switch and a schematic of the internals.
Drawing of the back of the Otto rocker switch and internal schematic.
Wiring of the switch is straight forward. Using the wiring for the fuel
pump as an example the “C” terminal is the voltage source to the switch … the
power comes from pin 29 of the fuselage connector which would normally go
directly back to the fuel pump. Terminal 1 goes to the load … in my case the wire
to the fuel pump. Terminal 3 is the ground for the internal LED in the switch which can be wired directly to ground … or, as I have done, wired so the LED can
be dimed for night flying by using the Cockpit Lights – wire from pin 18 of the
Options connector. The SkyView controls the lighting level by using a varying
resistance on the ground wire for the panel and cockpit lighting, so I
intercepted the Cockpit Light – lead and ran it to terminal 3 on the two panel switches,
then on aft to the cockpit light.
The white/yellow wire comes from pin 18 of the Options connector which
is the Cockpit Light – wire and is connected to terminal 3 (LED ground) of both switches.
The yellow/green wire is the wire that continues aft to the cockpit light
mounted on the roll bar and will supply the ground for the cockpit light. Of note, the
fuel pump switch is on the right and the left landing light switch is on the left.
As can be seen in the above photo, most of the wiring for the switches
completed during the work session except for two wires. All that is left to do
is connect the wire to the fuel pump and connect the power for the landing light
after adding a fuse to the circuit. Had
it not been for spending a huge chunk of time searching for the .092 Molex connector
pins (mentioned in the previous post) during the afternoon the switch wiring
would be completed.