Where to tap into switched power for head unit?

[Evan Bottcher]

Hi folks,

I am an electro-moron. Putting a new cheap head unit in our '81 Giulietta shitbox and the previous stereo was wired always-on. What's a good way to find a power wire that's switched with the ignition? I don't have access to a wiring diagram. I do have a multi-meter.

Thanks, Evan.

[GTVeloce]

From memory, the yellow wire going to the cigar lighter, at least on a 116 GTV.

[colcol]

Hey Evan on the 33,the wire can be different colors, but just use a test light to see if its live.
There are usually 2 wires, one for positive, one from ignition to switch the unit off and on and an battery powered wire to keep the memory going and for the clock.
On my head unit, the wire from the ignition had such a large voltage drop, that the unit would stop working at night when you pulled up at the traffic lights with your headlights going.
I ended up having to run a wire from the battery to the back of the unit with a relay, so that the relay is switched on by the ignition and supplied with good 12 volts from the battery.
Those 80's Alfa Romeo's really had bad wiring systems in them, Colin.

[Evan Bottcher]

Thanks folks I tapped into the cigarette lighter feed. Much appreciated. Holiday projects!