Hey guys!

I'm a new member here, it's my first time owning an older generation car and I'm loving it.
I'm a proud owner of a 1980 200b, it has a couple of electrical problems that I'd like help to fix!

The previous owner wired up an aftermarket headunit, he has somehow wired it in such a way that every time that the car is running my parkers stay on. I had a fiddle with the wiring behind the unit and now my tachometer has stopped functioning haha.
So I thought it was time I seek some help!
My electrical knowledge is very limited so I was hoping that maybe someone from the forum will be willing to help?
I don't mind paying a fellow member who's willing to have a go?

I'm located in Tullamarine but I'd be willing to travel anywhere in Melbourne.

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1981 Datsun 200B - Getting there!

dose the head unit have a good earth it defiantly sounds like an earthing problem to me.

Hey mate,

I am in Sydney, otherwise I would offer to help ..

Basically here is how each of your electronics works

The head unit needs 4 wires (generally) to get it going

Constant 12V - (Battery) - connected directly to the battery 12V (+) supply via a fuse.
Ignition 12V - 12V supply that comes on when key is turned to ACC
GND - Ground / Chasis / (-) side of the battery
Illumination - this is a 12V signal that gets power when your parkers/headlights are flicked on - this causes the head unit to dim at night and not be so in your face bright.

Then you also have
optional - antenna lift signal
And speaker wires :

front left +
front left -
front right +
front right -
rear left +
rear left -
rear right +
rear right -


Your tacho will only generally have 4 wires -
Ignition 12V
GND - Ground
Illumination
Tacho signal - runs to the (negative?) side of the ignition coil


I suspect somewhere along the line, someone has connected one of the head unit wires to the parker signal for the illumination line and is holding that signal when the head unit is on.

Hope this helps get to the end result.