Go into the menu and set the weather alert function to off. Here in the US, NOAA weather stations
transmit a alert tone for weather warnings and the 29LX will sound an alert tone (turn on?) even if the
radio off/on switch is set to off. Don't know if Canada has similar weather stations on same frequencies.
In this connection, when first powered up, the 29LX will turn on and then turn off to test the weather
alert function, even if the off/on switch is off. I don't think this is your problem, but try it and see.
It sounds more like something got shorted in the radio and it is getting power all the time until
you turn off the ignition power. The 29LX owners manual says it is warranted for 2 years from
purchase. I would also call Cobra for advice or go back to whoever installed the radio and
ask them to check it out. This radio has a great display and nice service features.