i just did this swap not to long ago. You can pick up the leds from where ever you want they are the festoon style bulb. Some led bulbs have resistors that are built in others do not thats why you might need a resistor. The reasoning behind this is that the led's draw less power so all you are doing is tricking the truck making it think stock bulbs are there so they function properly. So heres what i have a 20 led festoon panel in the over head then the maps have 16 led festoons in them and it looks like day light when they are on. superbrightleds.com is a great site and you can order all you dash/gauge bulbs from there too.(not a salesman just had great service and support from them on several differnt occasions)