No Sound -Harman Kardon stereo

[Micetee]

I bought a 2010 Subaru Legacy 3.6R limited with the Harmon Kardon stereo and navigation 6 months ago. The touchscreen has been non-responsive since I purchased the car but was able to work the sound through the stereo controls. 3 months ago, I brought it to the dealer to have the airbag recall work done and an alignment. Since then, there is no sound at all thru the stereo.

I recently purchased a used touchscreen stereo on eBay and the touchscreen and navigation now work but still have no sound. I tried AM FM Bluetooth, still nothing. I measured the resistance on the rear “subwoofer” since it was the most accessible and it measured 1.7 ohms. The amplifier under the passenger seat has power when I ground directly to the battery, but I can’t seem to get a reading when I ground to the wire at the amp (I found a wiring diagram from a Subaru Outback forum). This wiring diagram states that the amp is grounded at the “CENTER FRONT OF LUGGAGE COMPT”. I searched the trunk and couldn’t locate a ground. I think this is where the wiring diagram stops being accurate since its for an Outback. Looking for info on where the amp is grounded, or any other advice on what to check next.

Edited November 28, 2023 by Micetee