2003 Hyundai Santa Fe GLS with Monsoon head unit

I'm checking out the speakers around the car to consider upgrading. I'm not getting anything but a muffled sound from the tweeters on both sides, and the voltage on them is only 0.04 volts. I checked the voltage at the tweeter terminals, and at the wiring harness that they connect to? What are some possible causes for this?

 

Your meter may be measuring average voltage, check and see what you get on the lowest AC scale.

What kind of result do you get if you eliminated one of the speakers?