If your cigarette lighter adapter power cable does not seem to be powering the unit it is attached to, try these trouble shooting steps.
Many of these power cables have an LED that lights up when power is flowing through the cable.

If the LED on your power cable does not light up when it is connected to the external power source, the fuse inside may be blown inside or there may be a problem with the external power source.
To check/replace the fuse, unscrew the tip of the cable as shown below.

If this does not correct the problem with your unit, please go back to
Power On/Off Troubleshooting.