I ordered switchback led strips from eBay.
All three wires look clear.

How to check which wire is for what out of the 3?

What are my options to wire them without having to cut off sockets from stock harness?

I would like to avoid that as much as possible.

TIA

 

Take it over to the car battery terminals and touch the bare wires to the top posts. Process of elimination. One is white, one is amber, and one is ground.

Use these splice connectors to piggy-back off of the stock wiring harness:

And then coat them with Liquid Electrical Tape to seal them up.

although, the nicer ones have female spade connectors built into them to use with insulated male spade connectors:

 

Any progress? Interested in seeing some pics/vids of what you have going on...

 

No , i didn't get a chance to try it out yet or pick up an electronic flasher and scotch locks.
...life of a web devloper.

I didn't get a chance to look at your thread about the switchbacks , did yours get sorted out?