Wheel Loader Sound System

[ittigger]

Hello all, it's been awhile. I'm working on a Wheel Loader, looks exactly like this - https://www.youtube.com/watch?v=oE_DyZMXX3M, but it was purchased through RC Model Design (https://rcmodeldesign.com/all-products). Allegedly, it came with no manuals. The first problem was that the radio lost binding with the receiver. Upon binding, everything began working again, except sound. It appears to have 9 channels plugged into the receiver. I have figured out what buttons the auxiliary channels 'should' be on, based on youtube videos, like the one presented. I have mapped channels 1-5 and 7-8. No idea what 6 and 9 do. That said, I cannot for the life of me see where a speaker is, or should go. It looks like the lighting module sits directly beneath the receiver - but I haven't taken it out to verify.

Has anyone worked on these - and can help? Supposedly, when you plug the battery in, it should beep, you turn on the engine sound and then you can drive it, etc. When I plug the battery in, the beacon (flashing light) comes on, I can drive right away ... no sounds. I have disassembled the cab - there is nothing in or under it. There is nothing in the front - other than hydraulics. In the rear, we have the hydraulic well, pumps (servos), esc's (2), receiver and lighting module? I can find all the lights - and they all work as they are supposed to. No sound whatsoever.

Any ideas?