If you have a volt meter you should check at the tweeter terminals for voltage. If not you can pick one up from walmart for 20 bucks./// oops. its not too hard. Just select the V. Select the largest V value on the dial/buttons whatever you have. touch the terminals with the system powered./// ///If you are really unsure there should be youtube vids on using a dmm. some are automated and some require you to dial in just above the voltage you expect. Don't underdial it. DMM is the way to do it.///
If you have voltage and no sound it is likely a dead tweet. Volts don't flow, so presence of voltage just means voltage is getting there, not that current is moving through.
I am just speculating here, but you may be able to connect some mid range speakers or tweets to the crossover. If you just removed your factory speakers you may try those. Try the speakers you don't care about in place of the tweeters to see if anything comes through at all to see if it is crossovers. If you hear anything disconnect and conclude that your tweets aren't viable any longer. If you don't hear anything then your crossovers have problems or aren't being sent ANY higher frequencies, the latter not being likely.
When putting a sacrificial mid in place of a tweet, I do not know if this could be damaging to the amp or hu or whatnot. I would not think so, but I am not personally familiar with audio electronics.
I asked about the crossover frequency because I have heard if you push sufficiently lower frequencies you'll kill it. The specs that accompany the tweets should provide guidelines.