Kenwood DDX9907XR and Apple Carplay call issue

All,

I recently installed the head unit in the above title in a 2013 Hyundai Elantra Limited w/external amp. This is a unit I took off from an older car without external amp.

This was installed along with iDatalink Maestro RR2 and iDatalink analog RCA-to-SPDIF converter.

Everything worked fine after install, except for Apple Carplay calls... Others can hear me, but I could not hear them. No call issues with Android Auto or standard Bluetooth.

After lots of investigation and trying several things, I still couldn't get it working. A Google search turned up a few people posting about this same issue, but not much in response to a solution.

It turns out that different brands such as Pioneer have a disclaimer on this in their manual, where the most probably cause is the audio jacks to amplifier are connected to the REAR channel audio outputs rather than FRONT. When I checked the back of the Kenwood unit, sure enough they were connected to the Rear RCA audio outs, rather than front.

This is an easy mistake on some Kenwood units since the rear RCA outputs are the topmost ones, and the front channel are in the middle.

After connecting it to the front channel output instead, it resolved the apple carplay call issue for me.

I'm posing this because I couldn't find any direct solutions online when resolving the issue, and I'm hoping this helps someone else in the future who experiences a similar issue.