Put a working radio in a new truck, and now there is no audio receiving signals

Forgive me if this question has been asked. I had some issues navigating the search function.

So. Cobra 29LTD Chrome. Also regular Cobra 29. I've tried both CBs in this W900 that I've just gotten into, and I can transmit and receive. I have a decent carrier, because if I call out a radio check, I'll get responses indicated by the needle clearly jumping in proper signal fashion. But I've got no audio. Either from the CBs themselves or from the external speaker built in to the truck. My personal external speaker is at home, so that's not an option.

For both radios: Squelch is wide open. Rf gain is all the way up. Dynamike 100%. No ANT light on TX. I'm getting dirty background according to the needle. Internal SWR says antennas are a little long (again, both radios), but acceptable. I get out well enough for folks to hear me over short distances, at least, because I get clean signal responses. But no audio.

My 29LTD worked just fine 2 weeks ago in the previous truck, and it didn't face temperature extremes or rough handling in the vacation between trucks.

Help me Obi-Wan Kenobi...

 

Yep. No audio in receive. I didn't think of the mic thing. I'll have to try that out. Appreciate it.

 

I've tried both radios with the speaker plugged in and unplugged.

 

Update:

I pulled apart the connector on the mic cable, and sure enough, one of the wires was snapped off right at its attachment point to the connector. Mic is toast. It could probably (possibly) be fixed, but it's finer work than I want to do, and not something I'm going to pay for. Plus the mic was at least 9 years old.

I'm going to order a matching replacement and see how that goes. I've gotten compliments on how clean my CB sounds with the Astatic over the years, so why switch ponies mid-race?

The mic in question