New to forum and I've been searching for someone with the same issue but haven't found one. I just got my high school car back after passing it on to my niece, a 1998 mustang gt. I was pretty excited to get it back but was disappointed to see she had pulled the factory head unit and replaced it with a $30 generic hu. Also they used the wrong wiring kit bypassing the amps. So all that was working were the tweeters with no bass at all. I purchased the correct wire harness, a sony double din hu, and double din conversion kit. After installation only one of the back subs was working. I then purchased a new front amp and one rear amp. After installing the rear amp both back subs are now working. Changing the front amp did nothing. I can't get any of the tweeters or front subs to work. I think the front subs may just be blown though but I know the tweeters work, as that is all that was working before. I took a voltmeter and checked connections and measured the expected voltages. At a loss on what to do, I went to a car audio store and paid $125 for them to troubleshoot and they couldn't figure it out either. I was then quoted $2500 for them to install a new system. Has anyone had a similar issue, all I can find are no bass issues but I have the opposite issue. Only bass and no highs. Any help would be appreciated.