Alpine 3552

Amp Plays clean audio on 3 of the 4 channels ..

On channel 3 the amp will play clean audio for 2 secs then the audio cuts in and out over and over again .. It only does this on channel 3 ..

Is there a muting transistor or any ideas on what might cause he audio to cut in and out on channel 3?
 
No tapping on the board doesn't do anything .

I noticed when the audio tries to come back the amp will try to draw more current then when audio cuts out again the currier draw will
Go back to normal ..

It does this over and over and the current draw increases and decreases in time with the audio playing and cutting out