Bizarre Lane A/B Light Illumination (Video))

It appears you have LED Lamps and your schematic indicates you are missing the 1.5k shunt resistor in parallel with the LED and the 1k Series  Resistor.
Refer to the 912is Installation Manual Chapter 24-00-00, Page 32, Top Left Corner.

The circuit was initially designed with Incandescent lamps in mind.
LEDs will falsely illuminate from leakage currents in the OFF state.
The Shunt Resistor loads the circuit in the OFF state and bypasses the leakage current.

Bill Hertzel wrote:

It appears you have LED Lamps and your schematic indicates you are missing the 1.5k shunt resistor in parallel with the LED and the 1k Series  Resistor.
Refer to the 912is Installation Manual Chapter 24-00-00, Page 32, Top Left Corner.

The circuit was initially designed with Incandescent lamps in mind.
LEDs will falsely illuminate from leakage currents in the OFF state.
The Shunt Resistor loads the circuit in the OFF state and bypasses the leakage current.

Thanks Bill!

Ill take a look.

I have an RV-12iS too.  The ignition module with the Lane lights and switches is provided by Van’s.  Bill’s correct regarding Rotax’ circuit recommendation regarding the shunt resistor, but know there are over 1000 12iS flying today with this module.  It’s possible there is more on the circuit board than shown in the simplified schematic, as I can’t explain it either.

I assume you’re aware of the safety bulletin regarding the strain relief on the HIC module for the fuel pump wires.  The circuit for the Lane lamps run through the HIC module too, although on the 20-pin connector instead of the 8-pin fuel pump connector.  I’d suggest pulling the 20-pin HIC connector and looking into the connector to see if the pins are fully seated.  It’s possible there’s an intermittent connection occurring at the connector.  I’d do the same for the connector that plugs into the ignition module.  Just other possible points where there might be bad connections. 

Hello All,

I finally got time away from work late last night and was able to pull the avionics cover. Turns out I had multiple wires chafing and grounding out on the avionics tray. When I moved the wires off the tray the problem disappeared. I'm 99% confident this is the issue.

Also I apologize for posting here as I realize that this is a Rotax specific forum and many different airframes have different wiring and panel setups to integrate the Rotax parts. 

I wrongly assumed this was a Rotax problem because of the Lane lights.

That being said thank you all for the responses and advice!

The resistors are not the problem (unless its a bad connections and the blinking was relatated to vibration). The resistors provide current limiting because LEDs often can only handle 1V (unless they have internal resistors). The resistors drop the 12V rotax signal  down to a voltage appropriate for the LED.

The LED looks great when the lane is disabled. So they are working properly.