Simple question here... I picked up a 2005 TJ that has the factory underhood light... How do I turn it on?
I tried turning on the running lights, headlights, flashers... checked for a switch under the hood and inside the Jeep... and checked for a switch on the actual light itself.. but could never get it to shine. Does it have a positional 'mercury' switch inside the light itself??
Then I thought maybe the bulb is burned out.. but I couldn't see how it is removed... or opened... without force, but then I don't want to break it. Any help would be cool. Thanks.

Yep! Them are "mercury" switches. Nowadays they don't have mercury in them. Instead they operate on a GRAVITY principle. Unscrew it from the hood and while in your hands SHAKE it a little thisaway and thataway.. It might have a bit of rust in it and need to function a little to make the contacts get back together.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

HUH; I've wondered how that light works since I picked-up my Jeep last October. Are you telling me it can tell when the hood is down based upon it's relative position?

YES! That is what mercury switches did also..
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

Yes, those switches, whether the old mercury type or the newer "safe weight" type, are position sensitive. I've known several Jeepers to have switches that are so position sensitive that the underhood light comes on when they are going up a steep hill! The only time you'll know it is if you're 'wheelin' at night. Boy, I gotta tell ya, that looks weird as hell to bystanders when it happens! The first time it happened to a buddy of mind who was going up a really steep hill in Kentucky, it scared the hell out of his spotter, who thought the engine in my buddy's Jeep had caught fire!

Thanks a bunch for the info... I'll take it off and take it apart, 'cause now I want to know what it looks like inside.

Gone are the days of liquid metal and such 'toxic' things. Hell, we used to play with mercury when I was a kid..

I took the under hood light assembly off of my 1998 Jeep Wrangler last night. The bulb inside the assembly was smashed into pieces. Does anyone know the part number for the bulb? It didn't look like a regular bulb and there didn't seem to be a socket for the bulb to twist into. I am wondering if I need to get another assembly. Any ideas?

That's not a high usage item, so you might not get an answer here. Why don't you just go to the parts department at your local Jeep dealership and ask then for a bulb. You'll get to look at the diagram and see whether its the whole assembly or not.

im assuming the xj's are the same gravity based thing too right?

Unless there is a switch that is closed when the hood is raised...all under hood lighting is gravity switched.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />