My new micro charger will not work in my car. the cigarette lighter works fine. ?

I changed several cigarette lighters, and plug port. They all worked but my new micro charger for my blackberry doesn't work. I replaced the micro charger with a new one and that also will not work. There is power to the cigarette lighter because other accessories work. Any idea what's causing the problem? My cigarette lighter says it's 24v output which matches the micro charger.