Hi,
I just recently installed a fully loaded mtc thunderform box loaded with two ten inch subwoofers and class d amp into my 2000 f-150 lightning. I am getting nothing from the subwoofers at normal listening level. But if I adjust the balance to the left or the right, they subwoofers actually work. But then I'll only have speakers in half the car. Is this a power issue, will i need a bigger amp? Any help will be appreciated.

 

Sounds like the polarity of one of the inputs is reversed

 

Doesn't sound like a power thing to me, maybe crossed connections ie. left wire going to right side instead of left said type of deal.

 

Sounds like you need to go back through and check all your connections and make sure the wires are hooked up correctly. Are you running the amp form the speaker leads of the headunit?

 

Ditto. Input polarity is the problem. I specifically remember your situation in the troubleshooting Q&A when I installed my sub.

 

Stereo not Sterio!