A while ago I had a Kenwood Excelon DNX996XR installed but the issue was that the sound cut out randomly at first to no sound at any time now. No sound from any source (Apple Car Play, Radio, SD Card, etc.). When it was just random I couldn’t find any common denominator for when it stopped working. The shop checked all of connections and says all are good and tight. Now they are saying that the amp needs to be replaced but I wanted to first pick your brains here to see if you guys had any thoughts.

It’s a 2011 Limited with the JBL system.

Here’s a quick video showing that the system HU thinks it’s outputting sound.

Kenwood Excelon – no sound - YouTube

Here’s what was installed
Kenwood Excelon DNX996XR Navigation Receiver
SiriusXMT Connect Vehicle Tuner Model SXV300V1
iDatalink Maestro RR ADS-MRR Interface Module Part #: ADS-MRR
IDATALINK MAESTRO RR HARNESS TOYOTA TO1 Part #: HRN-RR-TO1
PAC BEST KITS TA2106B DASH KIT Double DIN for Toyota 4R 2010 – 2016 Part #: TA2106B
PAC BEST KITS BAA44 ANTENNA ADAPTER
InstallBay by Metra – 3' Dual USB Pass through Extension, Part #: IBR74

First suspect would definitely be wiring.

If you go into Settings / OEM Setup / Maestro Settings / Maestro Module / Diagnostics / OEM Systems / Amplifier. Does it show Retained/Detected/is on? Back up 2 menus on Inputs and Output, scroll down to Amp Turn On Input and Output and check to see they are on.

Do you still have your stock head unit you could plug in to see if it works?

It's probably the wiring. I'd go ahead and re-splice everything with good quality, adhesive heat shrink butt connectors, or solder if you have.

I just hooked up a DMX958XR in my 4runner, wiring all triple checked and connected using solid connections and im only getting sound out of the right rear speaker. subwoofer works too but nothing out of front or rear left.
My old deck works fine. Just checked it. Nothing wrong with my wiring whatsoever. Its definitely the unit.
I bought this thing "open box" from Crutchfield and i noticed the harness had been hooked up before as i seen rips in the wire ends on main wires.
Im almost positive this thing is blown. I have to call them Monday and i already threw away the box thinking it would work.
I cannot find any indicator that anything I connected is goofed up. My speakers are brand new and working on my other deck.
I spent $850 bucks on a open box deck.

I've been having a problem with mine cutting out as well. It started when using my remote start and it would pop my right dash speaker. I suspect that wiring may be an issue, but starting to wonder if it's the radio also

i just got my new replacement DMX958XR unit from crutchfield and 3 speakers out of 4 are still not playing sound. it must be the harness. connections are fine. this is insane. my older deck plugs in and sound plays in all speakers. it must be the harness. the harness on the "open box" unit i first received was used. im going to cut this harness out and use the new harness.
but why on earth would my old head unit play sound and this new unit plays sound from the rear passenger door speaker.
this is so ridiculous. i cannot figure out what the problem is. im getting ready to call a car radio company to have them figure it out.

man i cannot figure out WHY this 2nd brand new Kenwood will not play sound. I have a 2003 4runner SR5 which had a basic factory radio. no jbl.
harness connected perfectly and i only got sound from rear passenger in mid range. then i went back and changed the harness and hooked up all blue wires together and got sound from both rear speakers. still no sound from the front.
Does anyone know if youre supposed to wire the blue/white wire from head unit to the red ACC 12v wire from dash? Ive seen many people in videos do this and then they got sound. I know what the wire is for im just asking why are people hooking up the blue/white remote turn on wire to the red ACC switched 12v+ power?