the LED lights have a polarity, I put them in my dash and had to reverse some of them to get them to light up (at least thats all I could figure out why they would not work in one direction but would work in the other) but I took them all out because they are all really finicky on making contact,what I ended up doing was buying some green coloured 194's and taking the plastic caps off, it is bright enough now.

 

i have found no problem with mine so far. i know led's have a polarity so it was just common knowledge to turn the light around if it did not come on. i am still looking for good led marker and brake lights. i might have found a good backup light but i'm not sure.

 

I have seen different kinds of LED 3156 and 3157's, mostly in the tuner car section of Canadian tire, you have probably checked this out already, I was going to convert my truck to all LEDs due to the fact that my lights get left on from time to time (buzzer is broken) but I didn't follow through with it after changing my dash lights back to regular 194's

 

i have seen the ones at Canadian tire and tried some that where similar but none of them seem to be brighter than stock light bulbs. i have all the lights in the cab converted to led and they seem to work fairly good. the only thing is the white led that i used in the dome light can seem kind of creepy. it reminds me of the movie Christine.

 

I converted my front park/signal lights to those generic oval Orange LEDs that you see in big trucks. Just had to dremel the back of the old signal bulb housing to fit the new one. It is insanely bright and works fine. The park lights look slick at night.