So i thought changing the bulb would be easy, but i took it all apart and took the big light casing thing out, looks somewhat like hot glue on the back where the light plugs in, and i cant bust open the shell cause it looks like there caulking around it? how do i change the bulb?

 

if this is for lets say a 91 truck yours will have sealed headlights which means no replacing the bulb will have to replace the hole unit not very expensive ... or you can do a h4 conversion which is like a sealed one but it uses a h4 bulb that's replaceable