Strange stereo problem

The stereo in my car has stopped working (standard HU) doesnt light up or anything, however if you disconnect the baterry and then reconnect it, start the car up it will then work, untill i turn the car off again, then nothing.

its becoming a bit of a pain having to pop the bonnet everytime in order to listen to the radio.

anyone have any idea whats going on?
 
Remove the head unit , disconnect battery and try the whole reconnection in reverse, first the battery then head unit, could be a voltage issue or the head unit wiring is faulty.
Worth a try. GL
 
Make sure you're killing the bluetooth on your phone before troubleshooting. Mine was stuffing up the radio after an Android update.
 
Mine has done this a few times, it's also randomly locked itself but hasn't let me enter the code or press any other buttons. The screen has remained on though it's just the head unit itself that has turned off. If it's the same fault as mine you can also fix it by unplugging the radio for a while. After much much trawling the Internet the best answer I can find is its some sort of security thing;

Apparently back when radios started getting codes to use them, thieves discovered that if you stick one in a freezer for a while it unlocks. So the radio will disable itself if it gets too cold, but the head unit is obviously thinking it's too cold. Some answers I've found on the net have said Renault have replaced people's radios with Scandinavian spec ones once this has happened which have a better resistance to cold.

This may be a load of utter bull as it did take a lot of finding.