I thought I would throw this out there. I had to use one when we put LED turn signals on our Suzuki GSXR-750 crotch rocket. I want to put some LED tailights on my Challenger but our e-bodies come with 2 prong thermal flashers. Everyone says get a load resistor. Well don't. Go to WalMart or AutZone etc. and get an electronic flasher with the 3 prongs. Problem solved, see my pics.
Stole it off of ebay and cut and pasted the important stuff.
EDIT: Since I posted this I went through my other Electronic flasher and IT DOESN"T USE A GROUND WIRE. I think this is the more common one in stores. So you have to pull the connector out of your flasher plug to connect to the outside wires. If you ground the 3rd pin, like the first type, it will blow your fuse.
Check to see which type you have. The one sold on Ebay does use a ground wire.