Car radio battery wire zero voltage ! but original car radio is working when connected. Why?!

[lh333_34]

Just seen the connection pin out. OP, can you confirm exactly what

he problem/symptoms are.

Is there only the one plug in use ?


Blue/yellow should be constant 12v
grey should be switched 12v
black - ground -

pink - illumination
violet - dimmer


The other plug should be speakers ?

front spks

left + pink
left - purple

right + green
right - blue


rear spks

left + black
left - yellow

right + red
right - white


Do these colours make sense on your radio ?

Also would be better to use a test lamp rather than a multi meter.

Yes! Two plugs /harnesses ...as you mentioned

 

[LukeD]

WOuld suggest you locate the exact diagram that refers to the model you have . This will make a huge difference !

 

[lh333_34]

Just seen the connection pin out. OP, can you confirm exactly what the problem/symptoms are.

The symptoms are mentioned above. Every Voltage is normal when the original radio is connected. But when it is disconnected from the harness, No voltage on all wires in two harnesses.

 

[lh333_34]

WOuld suggest you locate the exact diagram that refers to the model you have . This will make a huge difference !

RADIO – Toyota ECHO 2004 – SYSTEM WIRING DIAGRAMS – Wiring diagrams for cars

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portal-diagnostov.com

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i found these diagrams upon your hint.

 

[Avo Mk8]

The symptoms are mentioned above. Every Voltage is normal when the original radio is connected. But when it is disconnected from the harness, No voltage on all wires in two harnesses.

Try doing your measurements with the -ve multimeter lead connected to chassis, not a pin on the plug.
I think your -ve lead may not be a ground connection (or it's being disconnected from ground with the radio removed?), despite it being a black wire!

 

[lh333_34]

thank you all so much! problem found! the black one is not ground, but the white/black is ! I have been following the wrong information from another webpage, saying that the black one is ground !
I just tested the blue/yellow (the battery wire) and the white/black, the reading is 12V ! while the original radio is disconnected.

 

[lh333_34]

WOuld suggest you locate the exact diagram that refers to the model you have . This will make a huge difference !

Good on you and the rest of the members joined this discovery. The correct diagram solved the puzzle! Thanks to everyone.

 

[LukeD]

thank you all so much! problem found! the black one is not ground, but the white/black is ! I have been following the wrong information from another webpage, saying that the black one is ground !
I just tested the blue/yellow (the battery wire) and the white/black, the reading is 12V ! while the original radio is disconnected.

Have chased many a Cr hifi loom and they can be murder ! probably even worse these days .My way years ago was to skip the stock cables for power and fit fused 12v cable and a better ground . Made huge difference .Also when adding relays for "120w " front bulbs !!! The stock loom cable would never work well.

 

[LukeD]

Good on you and the rest of the members joined this discovery. The correct diagram solved the puzzle! Thanks to everyone.

Its what we do... we spread the love .

 

[DPG]

Well spotted @AvoMk8 !

More words here.