I had a similar problem with a Pontiac some years back. It was a bad dashboard ground. It may not be it, but I would start there.
Well sometimes the radio is hooked up to the ignition itself. It is just the ignition wire, if it has a disconnecting face plate then you can turn it off by taking the face plate off. Or if you would like, you can pull the radio out and disconnect the wire from the ignition and it will not still be on when you cut the truck off.
IGNITION SWITCH, UR RADIO'S SECONDARY POWER COMES FROM THE IGNITION SWITCH SO WHEN U TURN YOUR CAR OFF THE RADIO AND OTHER ACCESSORIES TURN OFF AS WELL.
To reset a CLK radio, first turn off the vehicle and remove the key from the ignition. Then, press and hold the "Power" button on the radio for about 10-15 seconds until the display resets. If the radio has a reset button, you can also use a small tool to press that button. Finally, turn the ignition back on and check if the radio is functioning properly.
As soon as you turn on the ignition, make sure that the radio is off. Turn the ignition switch back off until the display goes off and turn it back on, then just push the hrs or min button to set the time.
To reset the radio code in a VW Beta 3 radio, first, turn on the radio and wait for the display to show "SAFE." Then, turn off the ignition and press the "TP" and "RDS" buttons simultaneously while turning the ignition back on. After that, you can enter the correct radio code using the preset buttons. If you don't have the code, you may need to consult your vehicle's manual or contact a Volkswagen dealer for assistance.
Check the ignition switch itself, sounds like it may be the problem.
YOU simply shut off the power switch to the radio and then turn off the ignition switch and when you restart the truck it should come out as long as the radio power is off
i have a 2001 mitsubish my radio want come on either
You turn on power to the accesories, ie radio, power outlet, etc.
move the steering wheel while attempting to turn ignition key
To reset the radio in a 1994 Volvo 940, start by turning off the ignition and removing the key. Next, locate the radio's fuse in the fuse box and remove it for about 10 seconds before reinserting it. Alternatively, you can press and hold the "Power" button on the radio for about 10 seconds to reset it. After resetting, turn the ignition back on and check if the radio is functioning properly.