You install your antenna, wire in the SWR meter, flip to a channel and key up to begin the process required to adjust the antenna. All of the lights are lit up and you can hear other people talking. But, when you depress the microphone button the meters needle barely moves, or fails to move at all. Even when you turn the "Set" knob to its maximum position nothing happens. You look at the meter on the radio and it doesn't move when you key up the microphone. What's going on? If faced with this dilemma, go check your radio's power connection, both positive and negative.
The LED's that light up your radio display do not require much power. Likewise, the receiver portion of the radio can receive with less than full power. But, your radio transmitter needs a lot more power. A high resistance connection (corrosion, partially broken wire, loose connection) can supply enough power to light up the radio's lights and LED's yet fail to supply all of the current that the radios transmitter circuits need. When this situation occurs, the transmitter doesn't transmit and the meter has nothing to read.
For best performance, make sure that those power leads are in good shape and are securely connected.