Head Unit wiring question

shabbyroad

can't search the forums so apologies if this is a regular question.

I'm about to replace my stock head unit with a Pioneer unit.

The car (Merc) has an ISO connector and according to everywhere I've asked/checked I should not need any adapter to connect to the Pioneer head unit.

The problem is that I'm not getting any power to the head unit. I've checked with my multimeter that there is power running right through the wiring and plugs.

I notice though that there is a connection/wire on the Pioneer for positive power from the ignition. I've checked some wiring diagrams online for ISO connectors and this seems to be missing from the ISO connector on the car side.

I have constant (negative) 12v at pin 4 and negative(earth) at pin 8.
What I don't have is ignition 12v at pin 7 and I don't see one anywhere.

I notice that a hands free kit that was installed has basically used the constant (negative) 12v to supply both negative 12v feeds to the car kit.

Is there any reason why I should not do the same thing with the head unit - that is : supply the pin 7 ignition connect with 12v from the pin 4 constant 12v ?

louie

You could wire the unit both red & yellow to the permanent power. It should work fine, but make syre you don't forget your radio on as it could run your battery down.

You should be able to find an ign. power at the cigarette lighter.

Red wire job is to turn On/Off the head unit.

shabbyroad

Thanks - I'll try that.

Can't understand how the factory-installed head unit got its ignition power though - perhaps the system in the car was able to turn the radio on/off via the optical connector that's there (there's a dash display for the audio in the car - probably not compatible with this pioneer I've just got).

shabbyroad

that sorted it - found an ignition feed to the ligher socket.

thanks louie

daveg

Did you get it fully installed Peter?