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I have a 2009 Multispace diesel 1.6. The original radio was replaced some years ago with a Sony Stereo which suddenly stopped working. I used a multimeter to confirm that 12.5 volts was being delivered to the final connector and checked the fuse in the radio was ok. No life at all so I bought a low cost Bosskzi radio. This does'nt powere up either so I am guessing the radios are ok and I am missing something in the vehicle. I attached my multimeter to the yellow and black wire terminals and get 12.5 v so I assume that earthing is taking place via the black wire. I also have the aerial plugged in.
Can the red ignition wire have anything to do with it. Something causing it to keep the radio without power irrespective of the ignition being switched on.

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    Radios usually have 3 power supply wires: Red, Yellow and Black. Black is ground, Red and Yellow are constant feed and post ignition feed (both +12V). Did you test both feed wires or just one of them? – IanC Jan 12 at 11:27
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    Thanks for the helpful response No power at the red wire so hopefully its just a fuse replacement - how do I indicate this answers the problem? – Ron Etherington Jan 12 at 18:37
  • Glad that helped! I posted it as an answer. You did test the wire with the ignition key turned on right? Sounds like either a burnt fuse (more likely) or faulty wire. Take a look at the fuse box and keep us posted! – IanC Jan 12 at 19:12
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There are 3 wires that power a car stereo: Red, Yellow and Black.

Car Wiring

  • Black wire is the ground. It can be tested connecting one end of a test lamp to the battery positive and the other end to the black wire.

  • Yellow wire is constant positive. It should feed +12V constantly, even with the ignition off. It can be tested connecting one end of a test lamp to some part of the car that is grounded and the other end on the wire.

  • Red wire is ignition positive. It should feed +12V when the ignition is on. It also can be tested connecting one end of a test lamp to some part of the car that is grounded and the other end on the wire, while the ignition is on.

Lamp test

All the tests can be done with a multimeter as well. If any of them fail, you might have a burnt fuse or a faulty wire. That would require a little bit more investigation to know where exactly the problem is, but you'll know where to begin.

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