05 4runner drl.

So I have a 05 4runner limited. It has drls. Ones in bumper. So basically it uses a 4157 dual filament bulb. I bought switch back 4157. But clearly they were sh bc they were hard to fit. Either way I got it in and it didn’t function as switch back. Then I realized I only have two wires going to the socket. A power and ground( I looked up wiring diagrams on mitchel) so why tf does it use a dual Filomena if it can only power one filament? I took org halogen out. Started my truck. One Filomena’s on. Used the signal. All it does is flash the same filament . So why is there a dual bulb?? How do I get switch back bulbs to work

 

It is impossible to use any dual filament bulb with just 2 wires, BUT here's what you need to do:
1 - Disable DRL via reprogramming, (procedure is available online - I saw it somewhere), or by changing your turn signal flasher to one without DRL.
2 - Purchase 2 new 3157/4157 sockets, (with 3 wires), to replace your existing sockets.
3 - Wire the original hot turn signal wire to the high/turn signal input wire of the new socket; the other wire of the socket gets wired to a Bosch type relay that provides 12V to the white light input of your switchback bulb,
and turns on only when the ignition is on.

I plan to do the same via a new adjustable turn signal flasher, as I installed LEDs, and they flash too fast. No problem with other LEDs, (headlights, dome, courtesy, reverse).