Steering Wheel Control Problem

[bfschroe]

2010 Highlander Limited with factory JBL radio.
Replaced radio with aftermarket Pioneer Z110BT with PAC-audio steering wheel control adapter (firmware 1.6.8) and the JBL compatible wiring harness.

All buttons work fine except the voice command button. When tested with voltmeter, the voice command button and volume down buttons seem to be putting out the same voltage so they cannot be differentiated by the PAC unit.

Replaced PAC unit, no difference.

Is this a defect or an incompatibility?

Has anyone seen this before OR has anyone successfully integrated these pieces?

Thanks
Bruce