Alpine system no sound. PLEASE HELP

[CCRamD]

So I just traded in my 14 tradesman for a 2010 ram 2500 diesel with super low mileage. It’s a great truck until one day I woke up and no sound coming out of the speakers. Factory head unit with u connect but no NAV. Truck does have the alpine system. I took the dash apart and checked wiring at the head unit and at the amp. All is good. I’ve tried unhooking the battery. I planned on changing the head unit anyway so went ahead and bought a new double din along with the PAC harness. Every thing works. Even the steering wheel buttons. Still no sound. So I broke down and bought another known good used factory amp. Hooked it up. No sound. I tested each individual speaker wire behind the head unit with a spare 6x9. And we have sound that way. But no sound to truck speakers. I took a door speaker out and a dash speaker out and tested to a head unit I had on a battery. They all have sound. So head unit is good. I know for a fact the amp is good because it worked in old truck. Speakers are good. I’m stumped. It has to be in the wiring. I’ve tested grounds. I’ve tested all power sources to the amp. Good. All I can think of is if this amp has a factory remote wire. The harness I used is a PAC RP4CH11 harness. Which has the remote wires that I attached to the head unit.
I’ve even just to check tried to hook the factory head unit back up to see if it works with the new amp, nope. Nothing. Please help.

 

[Hanover Fiste]

Disconnect the speaker harness from the amplifier, and test for speaker continuity. If it's good, then chances are the amplifier may not be getting a "turn-on" signal from the head unit.

 

[CCRamD]

Thanks for the reply. I’m understanding that this truck doesn’t have a remote wire turn on. Is this true? The computer turns the amplifier on called “data turn on”

 

[mtnrider]

Thanks for the reply. I’m understanding that this truck doesn’t have a remote wire turn on. Is this true? The computer turns the amplifier on called “data turn on”

Correct, there is no "turn on" wire, it's controlled by the Can Bus.


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[CCRamD]

So I have eliminated the head unit. The amp. I’ve eliminated the speakers. All being a problem. This “can bus” could it be bad? Can it be replaced? I’m trying to retain this garbage system as much as I can. But I’m tempted to just run all new wires to the speakers. Is there a way to test this “can bus”.