6 replies to this topic

[matt_tottenham]

I have just made a new dashboard with speakers and new head unit fitted, have installed it all as i thought would be correct, but obviously not. I checked the constant and ignition feeds with an electrical screwdriver, then checked online for which wires on the head unit were which, wired those 2 up, then earthed the unit with the cable from it to the bulk head. But no luck.

So, am i missing something obvious,

The unit is a Pioneer DEH-1220MP with yellow, red and black cables. Yellow being constant, red being ignition and black being earth according to the wonderful internet. And afte checking which wires are which in the car, red appears to be constant and black ignition. So from the unit-
yellow connects to red,
red connects to black
and black goes to earth.

Any advice would be much appreciated, thanks

[roberts]

most probably your aerial is disconnected...

[matt_tottenham]

Nope, not the aerial, as that is also plugged in. Would that affect the head unit turning on? it doesnt turn on at all, no lights or anything.

[roberts]

it acts as the earth, so without it nothing turns on.

[james962]

you are correct, yellow : constant live, red : ign live, black : earth.

Have you checked that there is actually 12v getting to the h/u with a multimeter? Electrical acrewdrivers are good for seeing if there is power, but they dont tell you how much. Also, is the earth clean? I.e. It is a good earth? If you have a multimeter you can check for continuity through the wire and earth point to ensure it is.

Couldn't be something obvious such as the fuse in the back of the h/u?

[Brams96]

And after checking which wires are which in the car, red appears to be constant and black ignition.

Black = ignition?? Doesn't sound right to me, black is normally earth.

So if your ignition wire isn't getting power the radio doesn't go. Try connecting the red & yellow H/U wires together and connecting them to the car red wire and see if it powers up then. If it does then you know you will need to find another ignition wire from somewhere. Remove the steering column cowling and trace the wire to under the dash and connect into that. Make sure your earth is touching bare metal not paint.

[matt_tottenham]

Im pretty sure the black in the car is ignition live, as it only gets power when the ignition switch is turned on, there is also another black cable that is the earth. So i will try using a multimeter, then checking the fuse in the headunit. and if that doesnt work, try connecting red and yellow together to see if its the ignition wire.

Thanks for all the advice, ill let you know how it goes.