Popping noise from rear right speaker after car wash

[black_escape]

I have a 2011 limited Escape and I went through a car wash yesterday and just out of no where 10 minutes after getting a car wash the rear right bass speaker was giving a very loud popping noise and then a A loud pitch and then a loud buzzing noise. It stays on for awhile and didn't go off I tried turning off the car and the sound was still there but fading away. I turn off the radio by removing the security insert as I have a avic x930bt and the sound faded away but was still there. Eventually it was just a low buzzing noise and then it turned off. This bass speaker is attached to the amplifier in the back and that is where the sound was coming from. Not sure if the happened because water is getting in there or the speaker is blown or the amp is bad. What can I do to test the bass speaker or the amp. I should mentioned I installed a backup camera and ran the wire on the side of the plug that goes from the top of the trunk to inside of the vechile I made sure I put silicon around the plug, I checked the plug it its sealed perfect. Checked in the back near the amp and there is no water on the inner liner inside of the plastic trim. Can it be the connection from my Avic to my Amp if so what wire should I check behind the HU? Drove the car today and there is no sound at all, not sure if it was just a fluke. Any suggestions will be much appreciated.

 

Thanks