i was fed up with having to have the key turned to listen to the radio, its inconvenient if you just want to sit outside the car, and dangerous as someone could jump and take off.
so I modified the wiring to allow the radio to work any time.
if you look at the connector on the rear, the 4 wires on the left are dark green, tan, light green and grey, they are thinner than most of the others.
do not touch these they are the speaker wires in a 2 speaker car.
near the centre of the connector is a thin yellow wire, if you put a test light on it it is live all the time, this runs the clock.
abovr that or sometimes below is a thicker yellow wire with a red stripe, or sometimes it is orange with a white stripe, it is only live when the key is on accessory or ignition, it runs the radio/cassette or cd.
cut these two wires, allow enough room from the connector to work on them if you cut it to close its hard to work on. insulate off the thicker wire so it does not cause problems whn driving. cut all the other wires and insulate them off, if you leave them connected you may get leakage of power when the radio is not being used leading to flat battery after a while standing.
solder the two yellow wires together and carefully insulate them off. i have a electric glue gun and after applying all the insulation tape or spaghetti I run a bead of glue all over the joints, that gives extra protection and is not too hard to remove if you have to. incidentally I also do this when wiring trailers and towbars etc. always buy good quality electrical insulation tape from an electrical supplier, the stuff you get at big W or most parts places is rubbish and falls off after a while, the good stuff is a bit more costly but a whole lot less problem.
yes this leaves the radio clock visible all the time but that is not a bad thing, and yes it is a constant drain on the battery, but this is not 1956 with 6 volt systems, a modern car radio draws practically no current, milliamps at most, and I have left a car standing for a month with no problems. if you get problems check the other systems in your car.