Rear seat controls

[mesa 33]

I have a 98xlt and when i got it it had a aftermarket radio in it. I noticed the rear seat controls for the people in the middle to adjust the radio isnt working. The audio guide that came with my explorer says to press 3 and 5 until the earphone pitcure comes on, but thats not doing anything but presetting either 5 or 3 to whatever station im on. Does anyone know whats wrong with it? Im not sure f it could be the harmness or not. thnks again

 

[section525]

It only works with the stock HU.

 

[mesa 33]

Dam that sucks well thanks anyways.