Good morning! I've installed a new head unit (tapped into the 12V orange wire from the cigarette lighter) on my 1972 Cutlass Supreme. Now I'm in the process of installing a low profile subwoofer under my seat. Would really like to get the 12V from the fuse box without having to splice my battery wire (and this is the root of my questions).

- can I splice off of the 12V wire that I've used on my head unit? Suspect that the answer here is no... worse case I could try and see if the fuse blows for the radio...
- what about other 12V constant sources in the car... any suggestions?
- and... it appears that the ACCY on the fuse panel (not in use for my car) is used for the power windows and cruise control.... could I use that to power the sub?

Any thoughts help prior experience is greatly appreciated... and if you tell me to splice the battery wire... I've got the parts so I'm ready to go. Just want to see if there is a cleaner / easier way that won't get me in trouble later.

Best,

Sean

 

Run a new 10gauge (at least) fused wire from the battery. That's the best way to power the sub.

 

X2 with above.

 

There should be a switched yellow 12v positive wire feeding the factory radio that is part of the accessory circuit. There should be an orange lead that is constant 12v feed for the memory circuit of digital radios. The gray wire is part of the dash lighting circuit so don't make the mistake of using it for a ground.

ANY self-respecting subwoofer will draw too much current for any factory circuit in your car. If the circuit is fused it will eventually blow the fuse. If it is not fused it will eventually overload the ignition switch and damage it. If your sub is a self-powered unit it should have a 12v constant lead that needs to be connected directly to the battery, not the car wiring, and a ground lead that needs to be connected to bare metal. It should also have a trigger lead that is designed to be connected to an output lead on the head unit. Accessory lead for factory radios. Do it right and you will avoid problems.

 

A fused 8 guage wire should be great to run from your battery to your sub's amp.

 

The size of the wire required depends on the size of the amplifier. 10 guage wire with a 30 amp fuse is usually adequate up to 200 watts RMS. I don't think anyone sells class-A amplifiers anymore so the current requirement will be very dynamic and rarely above 20 amps. More is almost always better but unless this is going to be a high performance audio system, the above should be enough for something that fits under the front seat.

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If you are talking about the remote wire on the amp. (the one that powers it on and off) then yes any 12v switched wire on the fuse box will work fine including the radio acc power. Now if you chose any wire under the dash as the power supply line for the amp you're just asking to burn your car to the ground! Watched My BOL use the lighter to power a 1000 watt amp once, talk about a fast way to strip a wire clean!