Hey everyone, I'm having an issue with my license plate light. I have a '99 Cherokee Sport and the light turns on when the Jeep is running. Once I turn on the headlights, it goes out... I really have no clue what's going on here, I've checked connections and can't find anything. Any ideas?

Strange my license plate light only comes on when the lift gate isn't shut or it is open! Lights on or off or the xj running or not same results for me.

Probably a broken wire somewhere and it makes the connection when it's open because the wire is moved to where it's making contact. Time to take apart your liftgate!!

Would that also have the same effect on the wiper motor power?

are you having problems with the wiper motor too? Even if you aren't it still doesn't matter. Just because one wire breaks doesn't mean another will. I would open the liftgate and check for power using a test light,

Oh... I never saw the part about it working, but not workin with the headlights. It's like backwards! Does it work with running lights?

Mine does. Anytime the lights are just plain goofy, I check the grounds.

Bingo.

No it isn't working with the running lights either.

It seems that the license plate light and/or the wiper motor will not work if the liftgate is closed properly.

Today I opened the liftgate and the car door the light comes on close the door the light is still on. The dome light works off of the door but not the liftgate. When I try to push the dome light in, as it is a switch able light, to turn it on or off the license plate light goes either on or off. Like the dome light switch is controlling the license plate lamp when the liftgate is open.

I can hold the handle of the liftgate up like I am opening it and take a screwdriver to simulate the gate closing into the latch mechanism and the light goes on and off also.

I will be pulling the trim off and looking more into it but I do not know where to begin? I know if the liftgate is open the circuit works good. If I shut the gate the circuit stops working. Could it be a connection from the dash and the lights switch that is causing this? A PO had some sort of alarm in the help at one point and the wiring under the dash I had to push back up when I bought it back in March...

One trick for checking grounds there, (it IS fiberglass you know), find a nice long wire like an old vacuum cleaner cord and clamp one end right on the battery Negative. Then touch the other on the bulb socket. (or any suspected bad ground)

Or use your jumper cable and a shorter wire.

What can happen with a bad ground is things "back feeding", hence the goofy stuff that makes no sense. Something easy to rule out in any case.

Sounds like a good trick! Our tip! Will have to try it. But couldn't I use a good ground point on the rear of the jeep instead of going to the battery?