PM400 with an Amplified Speaker

[KC9LEA]

Have a customer that has an existing PM400 as a dispatch radio, and wants to add an external amplified speaker so the mechanics in the garage can hear the radio, along with the dispatcher in the office(using the internal speaker). The speaker they provided is a HSN4035C. We clipped the MCS style speaker connector off, wired it up to the PM400 on pins 1 and 16 in the back, and we arent getting any audio(yes its powered on). We tested the pins with a regular motorola external speaker and it works fine. Anyone have any input on why we arent getting any audio out of the amp speaker?

Thanks In Advance!!

[RadioSouth]

Audio wires from PM400 to amplified speaker correctly polarized ? (Would fire standalone speaker either way but might be a no go to the amp).

[KC9LEA]

I believe it is, but if anyone has a pinout, it would be greatly appreciated.