I think the tweeters on your speakers are soldiered to the internal speaker wires. If that's the case, you can use a multi meter to see if anything is making it to the tweeter. Just touch the 2 multimeter probes to the soldier points and see if you are getting any readings. It would probably be best to play something consistent, like white noise, and check both tweeters just so you have a reference.
Tweeter Problem
I have a pair of EG Andra III's and the tweeter is not working on one or the Andra's. I haven't tried swapping them around yet to see if it's the amp but I doubt it because the mid-range is still ok. How can I tell if it's a problem with the crossover or the tweeter? It's a bi-wired system.