Resistors are required? That's funny.. Because I didn't install them and mine flash fine. All I installed was an EP27 electronic flasher, which is designed for LED bulbs. They hyperflashed with the OEM flasher, but once I installed the EP27 they flashed normal, and still do.
You can pick up that flasher at any autoparts store, generally an in-stock item for around $10-15.
Keep in mind, if you do go with the DDM switchbacks (Autolumination.com also sells the same style) that do not disable the white circuit (parking) when the amber (turn signal) is flashing. This makes them flash Amber, white, amber, white, amber, white, etc.
Other sources, such as vleds.com sells the style that completely disables the white circuit when the amber is flashing. This makes them flash Amber, light off, amber, light off, amber, light off, etc.
Here are some videos if you still cannot understand the difference.
DDM and Autolumination style:
Switchback 3157's on a Dodge SRT-4 - YouTube
Vleds.com style (The ones I had in my Durango, and now have in my Cummins)
Daytime, but with a sequential flasher unit (The reason I needed the style that completely shut off the white circuit while they flashed)
The switchbacks I ran in my Durango and now I run in my Cummins were purchased a year ago from a seller on eBay. Each bulb has a total of 120 SMT LED's. 40 are white, and 80 are amber. The seller's name on eBay is str_led_lighting. He ships from the US, and is very quick. I've purchased 6 pairs of them from him with not a SINGLE issue.
Here is a link:
2 Pcs 3157 120 SMD LED Switch Back Dual Colors 80pcs Amber 40pcs White LED | eBay
