lets talk festoons....578 is the festoon bulb # for the dome light of an 06 and up dakota. what mm does a 578 measure as many sites such as vleds list festoons by mm.

 

the rear festoon is the 211-2, 42mm on vleds.com....and the front festoons are either the 31 or 33mm festoons. My head is leaning towards the 33mm though because i notice in a lot of cars that when u buy a short festoon it comes up a coouple mm short and it needs to be modified...I have an 05 dakota so my front dome lights use the 194 bulbs...

 

do you have the overhead console? i dont...i would think my dome lights are the same...they have the same housing and look the same

 

yes i have the overhead console, but in 2005 they put 194 bulbs in the dome lights, and starting in 2006 they put in festoons instead.