For those of you that used the Metra 72-5600 wire harness speakers adapters when you upgraded your speakers on Mustangs and other Ford cars and trucks, there's a good chance you now have a reversed polarity problem. Even if you had an audio shop do the work, your new speakers might be wired wrong if the shop used the Metra 72-5600 adapters. It appears that this problem is VERY common. I bought two pair of them (total of 4) in sealed Metra bags that had the polarity reversed. I called Metra...

Metra 72-5600 speaker wire adapter polarity reversed