so when i bought the car used the left speaker didnt work, i replaced them with a free install and they fixed it, but sometimes the front speakers would not always come on or it would only be the treble with no bass. i looked inside and someone had cut all the wires and electricall taped them back together, probably cause the previous owner didnt buy the adapter harness. i soldered them back together and now basically every other time i drive my car my left speaker loses bass. it seems like whenever i leave it in the sun or its hot, idk. i guess i could try and resolder the wire again, any other suggestions??

 

make sure the polarity of the wires are correct. give more details of the setup. (all stock; aftermarket speakers; aftermarket head unit?)

 

pioneer 3 ways in the front, 4 ways in the back, panasonic 8100 i think