Wiring help on car with no HU in it already

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Jul 6, 2005 | 07:54 AM

JordyO

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I'm about to install an Alpine HU in to a car that doesn't have any wiring for a HU in it yet.

I would normally just use a wiring harness, but that's not really an option.

So the Pos + Neg are pretty easy to figure out, but how should I wire the ACC? I'm obviously going to have to tap off another switched source, but where/how?

thx [img]graemlins/thumb.gif[/img]

(I think it's ACC.. the one that has switched power to allow it to turn on/off when the car is on or off.. .. grr.. brain fart, I can't think of the name of it right now!)

Jul 6, 2005 | 10:13 AM

Dereck Waller

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Yup, it's accessory you are looking for. What kind of car is it? Generally I would go to the ignition wires and use a meter to find the correct wire and solder my lead on with a fuse pretty close to the connection.

Jul 6, 2005 | 10:15 AM

JordyO

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Car? .. hehe, not one you have ever seen before

actually it's for the Panda... it doesn't come with a radio or even a spot to put it, so I have to figure out how to get one in there on my own.

I'll do what you said with the ACC wire though.

15a fuse should be good?

Jul 6, 2005 | 10:37 AM

Dereck Waller

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15 will be fine, I usually use a 10. I wouldn't be surprised if DEI Techsoft didn't have wiring info on that car. [img]graemlins/thumb.gif[/img]

Jul 6, 2005 | 12:01 PM

timmyturtle

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I had the same situation: just use a test light to find a positive lead that is also on switched power (preferably one that you wouldn't use while also using the HU). Not recommended, but another option is going from the fuse box (as you'd be basically doing the same thing: tapping into an existing run). Cheers.

Jul 6, 2005 | 12:49 PM

JordyO

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Awesome... thanks everyone [img]graemlins/thumb.gif[/img]

Jul 6, 2005 | 03:33 PM

Dereck Waller

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You could do it the way Timmyturtle said, but you never know what other circuits could be using that lead. If you want real rocksteady voltage you could use a relay, use the acc lead from the vehicle to trigger it and get the acc power straight from the battery. I had to do this with my beetle as there was so much electrical noise in the factory wiring.

terminals as follows
85 - ground
86 - acc feed from vehicle
87 - wire straight to battery with fuse at battery
30 - to head unit accessory wire.

This will make sure that the cars wiring will have no affect on your head unit. If you are running a wire from the battery for constant it is very easy to do.