I bought RED leds to replace the incandescent 1157's in my brake/signal lights. I also added the third brake light, had to run a new wire upto the brake light switch for the 3rd brake light as tapping nearby wiring would have the 3rd light come on with the turn signal
Side by side comnparison with a 3196 bulb, which is 150 more lumens than an 1157, IIRC, the LED was slightly brighter, and a deeper red color, making the incandescent appear almost orange in comparison. I got a few opinions asking them to look at the brakes and flashers from all angles and the opinions were the same or they could tell no difference until the hazard flashers were on and the LED fired full on full off instantly where the incandescent was a slower rise and fall.
Older vehicles with dimpled lenses work better with LED bulbs than newer veicles whose reflectors are dimpled, each dimple reflecting an image of the incandescent filament.
One major thing to worry about with LED drop in bulbs in signal fixtures is the 'dual filament' bulbs. Many do not have enough brightness difference between running lights, and brake/ signal lights. SO one cannot see that the car in front is indeed braking, or thinks the person ahead is driving around with a foot on the brakes
Many also cannot be seen well at angles other than from right behind. While LEDs behind red lenses make for pink brake lights.
The make digital flashers. I did not need load resistors.
I tried some Amber LEDs in my front amber turn signals but they proved obnoxiously irritating, and I went back to 3196 incandescent bulbs up there.
LEDs tend to get dimmer when hot, So I held the brake down for 5 minutes at 14.7v, and the LED did get much closer to the Incandescent 3196 in intensity and was only marginally brighter once it was hot.
Mine draw 0.56 amps on high and 0.12 amps on low, IIRC.
http://www.thetruthaboutcars.com/2015/03/piston-slap-traversing-world-led-retrofit-bulbs/
