Tweeters not working after new head unit from a 2004 3 series

I have a 2000 328i and replaced the head unit with a cd player from a 2004 3 series that way I could get the after market aux cable. now the tweeters dont work. Any ideas?

Originally Posted by stewboy55

I have a 2000 328i and replaced the head unit with a cd player from a 2004 3 series that way I could get the after market aux cable. now the tweeters dont work. Any ideas?

Did you wire it up correctly?

+1 on wiring and Delmarco told me that it's best to disconnect the battery when swapping head units.

yeah its still a BMW head unit. all you have to do is unplug the old on and plug in the new one.

Originally Posted by stewboy55

yeah its still a BMW head unit. all you have to do is unplug the old on and plug in the new one.

Since I'm assuming you bought this used....are we sure that there isn't an issue with the new HU?

I'd like to plug the old one back in and see if the tweeters come back.


If they do then its the HU

If they don't....well we'll worry about that later.

yeah I don't remember if they worked with the old HU. I didn't notice they weren't working until my dad got in my car. he told me they worked when I had the old tape player HU in it. I will have to check when I get time

First rule of trouble shooting is to work backwards and make it work the way it did before making changes.

Let us know how you make out.

If the rest of the front speakers work it's not the head unit. The tweeters are wired forward from at amp in the trunk.