So the other day I decided to do the BCM fix because I was getting no stereo at all. Now that I did that my subwoofer and the speakers that are under my seat will randomly cut out. I didn't do the install it was in when I got the car. I've changed the fuses and that hasn't changed it. Unless its a connection issue, I have no clue. There are 3 amps mounted on the back of the trunk and I assume they power the sub and speakers under the seat. The light will go out on the amp randomly and no bass. If anyone has some insight it would be much appreciated. If you need more specific info like amp or sub brands I'll add whatever I need to. Thanks in advance.

 

Oh and it also makes a thump noise when you start the car.

 

Is a little activation "remote" wire turning the amps on? They are usually pretty flimsy leads coming from the HU and I've had issues trying to use quick-splice connectors to daisy chain them. It's better just run a real speaker wire from each amps remote turn-on port to the next amp.

 

Check the connections at:
-Alternator
-Battery (both terminals)
-Source of positive wire for amp (maybe at battery terminal, maybe alternator, or wherever else)
-Ground point for amps
-Amp terminals

Nothing should be loose or corroded. For the ground, it should be on a structural piece - I used the upper seatbelt mount bolt when I had my Camaro. Make sure the paint has been scraped off because paint is an electrical insulator.


Measure voltages:
-Between remote terminals and chassis ground (should be between 12-14v) - if not then the H/U is bad or the remote wire itself is bad or loose or 3 amps is too much for the remote output and it needs to be buffered with a transistor or op amp - NOT!!!! with a relay (the sense coils are pretty low impedance and I wouldn't want to see one run with a low-power remote output). You can test the last case by running the remote wire ONLY to the sub amp and removing the connection to the others temporarily. If it still cuts out then it's not the problem.
-Between power terminals and chassis ground (should be between 12-14v) - If it drops with volume then you have a bad connection, too small a power wire, too small a ground wire, need the "big 3" upgraded, have too weak an alternator, and/or have a tired battery
-Between ground terminals and chassis ground (should be a fraction of a volt at most) - If it's higher than a fraction of a volt then your ground connection is bad or the wire is too small
-Between power terminals and battery positive (you can use an extra wire if your multimeter's leads aren't long enough for this) (should be a fraction of a volt at most) - If it's higher than a fraction of a volt then the wiring between the battery and amp (be it something in the big 3 or the amp power wire run to the back) contains a bad connection or is just too small

All of those should be true, even with the volume cranked up.


If the lights are going off on the amp then either one of the above things is the problem or the amp is bad.