Recently carried out a fault find/repair on some ones CB setup. Isolated the problems (no audio, no transmit) to the microphone. The unit left the factory faulty, and had never worked! I assumed the microphone plug had been wired incorrectly but turned out to be a broken wire in the hand unit itself, another crappy silver solder dry joint victim - bring back lead! 

 

Anyway for reference the MIDLAND 98 PLUS standard Midland microphone (the large one with channel up/down buttons and UK/EURO button) is wired as thus...