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914World.com _ 914World Garage _ After market Radio wiring questions

Posted by: pgollender Jan 25 2015, 10:49 AM

I decided to update my fuse box with a J-West box. ( Much nicer) and at the same time install an after market SONY digital radio. I need help with where to locate or "splice"
the new wiring.
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There is a yellow 12V power wire that supposedly stays on all the time as you dont lose your presets.
A red wire that is the 12V "Key On accessory wire"
and an Orange/white wire that is an "illumination wire" that dims your new radio lights when the headlights are activated.
Where is the best place to attach/splice/locate these wires ?
Last time I added an after market radio was pre-digital and just attached the one radio line to the cigarette lead. Attached Image

Posted by: Steve Jan 25 2015, 11:00 AM

I ran the illumination wire to the gauge lights with my Alpine. It works, but not very well. For the ignition wire, I created an accessory switch using a single pole double throw toggle switch. Switch up allows me to listen to the stereo without the ignition being on. Switch down, means that the stereo will only come on with the ignition on or when the car is started. My ignition connection comes from the cigarette lighter and the battery connection comes from the fuse box. I also put an amplifier in the front trunk and have an electric antenna.

Posted by: malcolm2 Jan 25 2015, 11:05 AM

you got the radio requirements, now you just need to find what is what on the car.

My memory is not to good on what I did, but I do have a nice color wiring diagram.

The instrument lights on your car have a black wire with a blue stripe. If you use that for illumination, they will dim when you dim your dash lights. Get you some of the mid way pinch splice connectors. Tap into the Blk/blu wire, with the 3rd wire going to your radio.
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I know I did that for my aftermaket gauges. My radio used the power to illuminate all the time, no dimming.

I think I then got a couple spade connectors like this....

and connected them to the correct place on my J-west fuse panel. RED wires in your car should be 12V all the time. There is one on the far right of my panel that is red on both sides of the panel (straight thru but fused) add the connector to the fused side add your all time power wire to that side.

The car's panel has a YELLOW wire the same way for the head lights. They are only on if the car is on. Do the same thing on the fused side of it.

The 1st connector will work the same way. Just use a spade connector somewhere so you can remove the unit without cutting wires.

I use a Blaupunct head unit. It has a cool feature. If the car is not running. I push the control button on the radio and it turns on. It will stay on for 1 hour. That way I don't need a switch, or the key to even be in the car.

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Good Luck,

Clark

Posted by: Dave_Darling Jan 25 2015, 01:26 PM

Don't use those "vampire taps", please! They create more problems than they solve...

The piggyback connectors (shown in the second pic in Clark's post) are what you need. Find where the wires you need plug in, and plug them into one of those instead.

Wires you will need (gleaned from the 74 wiring diagram, as that's what I have and you didn't specify the year of your 914) :
- Red/white : Switched power, gets +12V when the key is on
- Solid red: Unswitched power
- Brown: Ground
- Black/blue: Instrument illumination, goes through the dimmer on the light switch
- Red/white and black/blue together on pin 56 of the headlight switch: Headlight power, gets +12V when the headlights are on

The stock fuse panel has extra lugs for the constant power and the switched power. I think the JWest panel likely does as well, so you should be able to plug into those. If not, then use the piggyback connector for those circuits.

For the illumination wire, I would put a piggyback connector on pin 56 of the headlight switch. You probably don't want a signal that's gone through a dimmer for that.

--DD

Posted by: pgollender Jan 28 2015, 01:33 AM

The car is a 1970.
Thanks I've got them all hooked up with the Piggyback connectors.
Switched, constant 12volt red and Mr. Piggy on pin 56 on the headlamp for the illumination function wire.
Nice and clean installation.
Still a few weeks away from turning the key. Will repost when theory becomes reality. Attached Image

Posted by: 72 IXXIV Feb 25 2015, 11:16 AM

I'm looking at building a power amp/line volume preamp for iPhone audio. The 300W amp I'm looking at (Fosgate PBR300x2) recommends running power directly off of the battery, not the fuse box.

Is that kind of power going to over-tax my 43yo wiring? It would be so much easier to tie into the fuse box, but will that be reliable with that kind of current draw?

Thanks teeners!
chris

Posted by: Dave_Darling Feb 25 2015, 02:36 PM

300W RMS, or peak? Or "sound power level"?

Let's see. 300W / 14v ~= 21 amps. (More if the rated power is RMS.) I don't think any of the wires in the car, except for the one from the battery to the starter, are going to last long running 21 amps through them.

Hook the amp directly to the battery, and use a wire that is thick enough to handle the current. Also install a fuse within ~18" wire run of the battery on that wire.

--DD

Posted by: 72 IXXIV Feb 25 2015, 02:47 PM

Thanks, Dave.

They sell a kit with the fused cable and everything--I think I'll pick one up.

I'll wire my preamp and USB power supply to the fuse box.

Posted by: r_towle Feb 25 2015, 04:49 PM

For me, stereos and especially amps get wired right to the batter with the correct fuses for each. It's cleaner power.