Audio Systems: 91 lebaron radio/cassette, infinity system, radio cassete

Question
Ithink i have a bad amp. where is the amp located?Infinity system..Replaced radio/cassete head same problem.Some treble only sound coming from all spkrs. on full vol. only.Have 12v. at all spkrs.

Answer
there are 4 amplifiers  each door speaker with amplifier behind the speaker
you need to find the relay that powers all this amplifiers it is in the radio location right side
or check all the fuses there are 3 fuses for the audio system
good luck