No audio to JBL Synthesis system

Hi everyone,

I just bought a 2004 Limited V8 4WD with the JBL Synthesis system. The issue with it is no audio is populating. There is power, and all controls work except the audio. When I turn the volume knob, no numbers appear, and the same goes for if I use the steering control buttons. I replaced the fuses in the engine bay, on the left below the steering wheel, and removed all the dash pieces to disconnect and reconnect all wire harnesses to the head unit. I repeated that process on all wiring harnesses behind the panel in the trunk on passenger side. Is there an issue with the head unit itself, or do I need to replace some wires? I am at a loss

 

welcome

 

Since you say nothing happens even when turning the volume knob on the Head Unit (no volume numbers changing) i'd say something is wrong with the head unit itself. I have the JBL Synthesis system in my 2004, but i've since replaced the Head Unit with a newer Scion Head Unit (known upgrade) and i can't remember if volume numbers actually appeared on the original Head Unit or not. Check the connections to the JBL amp as well, if you haven't. I believe its back on the passenger side rear tire well underneath a bunch of interior parts. Kind of a pain to get to.

 

I have a 2004 with the JBL system and the knob on mine either works very sporadically or not at all, so I use the volume controls on the steering wheel with no issues, the volume numbers should show on the display, since yours is not showing at all tells me it has to be the head unit gone bad and needs to be replaced.

 

Update: So I replaced the head unit, and I’m still having the same issue. The steering wheel does look like it’s been hit pretty hard, like someone was road raging and punched the horn. Could there be an issue with the steering wheel that is causing the volume to not work? I am starting to feel pretty beat down because I have replaced everything except the steering wheel at this point. I was originally going to only replace the air bag unit, but now it was recommended to me by a friend that I’ll probably have the replace the entire steering wheel unit itself. I’m hoping someone will have an alternative to help me that isn’t that :/

What else can I try before resorting to that full replacement?

 

Since the actual head unit (new) still doesn't change the volume.. have you physically checked the connections to the JBL amp in the back?

 

Yes, I disconnected and reconnected them all. When that didn’t work, I replaced the JBL amp itself. It still didn’t work, not entirely sure what to do now. Replace the sub itself?

 

I recently changed the sub-woofer in mine. When I disconnected it there was no sound and I don't think anything appeared in the display either. I put a new sub in and it worked fine, volume number appear, sound is fine. I believe that all speakers have to be connected or the unit won't turn on; safety measure to keep from blowing the amp or head unit.