Three green gear down conversion?
 

Does anyone here have any experience with converting the single green gear downlight to one light for each down and locked gear?

STC required?
Field approval?
How to wire it without changing the existing single down and locked light that is activated by three down and locked switches that are wired in series from the nose to right to left to the lightbulb?

Thanks,

Rick

Three green gear down conversion?
 

RICK. As an A&P and '65 C337 owner. The simple answer is YES, if there is an STC you'd have to use it OR DER field approval! Field approvals are long expensive exercise dealing with the FAA. The wiring would be fairly simple. I wired separate wires from each up-locks to three separate toggle switches on a test board, which had a molex connector, to test each up-lock. BUT this was only for maintenance checks, so it does apply to airworthiness requirements!
FYI: I too would like three indicator lights! If you find a STC, let me know!! BILLS

Well,

If you DO have a green light, they are down and locked.

If you do NOT have the green light
then look left and right to the sides

If the gear legs are sticking out to the sides
they are down.
Maybe not fully locked, but not an issue for landing
They WILL stay in position.

So the only thing left is you MAY have a nose gear problem.
The best means to address being a wing mounted mirror so you can see underneath.

The system is DAISY CHAINED together so if there's a green light all switches have been met. This does not include any mismatched, problem systems but if you have a problem you will know it. It's a pretty simple system so why complicate things with more switches that can go wrong?