I am new to car wiring and I used the wiring diagrams on this site to fit a new CD changer into my car.
The problem being, I wired the purple (switched live) to the power for the head unit, yet the player will only work when i have my lights on O_o
You have the power wire attached to the Illumination wire. What year is your BMW?
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Do it right the first time
1989
Im using the wiring that was already in there... one friend sujests re-wiring completely but im not to sure how. ive only just really started working on cars so i dont know much about them.
there should have been a 4 pin plug on the factory radio, 12v constant, 12v ignition, ground , and illumination. test them to see which one is which, and if they dont test check your fuses.you can run new power wires but its easier using the factory wires because everything you need is already there.
the factory switched live (purple) is seems to be wired to the illumination fuse and the constant is as dead as a dodo. I have changed the fuse and thats not whats wrong unfortunatly. also i think the last people to wire the car took the power for the rev counter from the sterio because it doesnt work now and all i did was disconnect the old sterio >.<
sounds like the previous owner tried fitting a stereo with a speed pulse pick up and tapped into the rev counter by mistake or its feeding back through the stereo becuase the correct feed has a fuse blown on it.
go through all the fuses on the vehicle you will find there will be another fuse blown it will probably seem to be an un-related circiut that should bring back your permanant supply
once you have your + - & ign you can power up and probably will find it easier to link the stereo illumination to the ign supply.