12V Permanent feed fluctuating?

Hello,

Bit of a strange one for you guys:

Over the course of the last few weeks I noticed that the CD player in my Defender kept loosing its settings - 12V permanent feed for memory seemed like the most likely cause. It got to the point earlier this week where the radio wouldn't turn on at all, so I explored a little today...

I have discovered that the 12V permanent feed seems to be fluctuating. It goes from anything between 1V to 11V but never actually sits steadily at 12V. The Ignition live is absolutely fine and so is the earth connection. The radio needs both 12V feeds in order to work, so does anyone have any ideas what's going on here?

I have looked for breaks in the wire / loose connections but nothing has shown up. I have tested the radio with a different setup and it works perfectly.

I'm a bit scuppered!

Cheers,

-Tom

Tom, how did you test the voltage? And did you use a DVM?

Sounds like a bad connection, I have seen over the years fuses broken not blown or wire broken inside but the insulation still intact.

I would trace the wire back to the supply source and measure it there start probing the cable (tape up after) and work back to radio.

Regards
Lee

I would carry out a voltage drop test to pinpoint where voltage is being lost. Rather than trying to explain it on here. This is a video of how to perform the test on a starting circuit but cn be applied to your problem with power on to the radio. Voltage Drop Test - Made Easy - YouTube
Cheers

If you know the live feed is good up to the ignition why not replace it from ignition to radio. .. and double check the earths my radio flickered on and off it was earthed to the metal of the fuse box I ran a wire to the battery and its sorted

Definitely seems like a flaky connection / wire prob, wires often fracture within the insulation, almost impossible to find exact point, so try running a totally new connection from known good feed point.

Try using a test lamp instead of a DVM.

DVM uses no current at all ( which is the same as the radio ).

The fault will probably be really obvious if you put a little load on it.

A 5w indicator repeater is a good test lamp for this kind of work.