Seeking help with custom car stereo wiring

[lordbear]

I am hoping someone can help me find some information to assist me in a small car stereo project.

My 2001 Dodge Neon's factory 4-disc CD player died. I've already removed it. I don't miss it.

I get my music from my smartphone using a cassette adapter that has a standard 3.5 mm stereo headphone plug. I'd like to 'upgrade' my sound quality from the cassette adapter by connecting my smartphone directly into the CD player input connector on the stereo head unit.

I already have an adapter harness with the compatible connector on the head unit side. The connector on the other end is inconsequential. My plan is to find the pin-outs for the CD player input on the headunit and then custom wire a standard stereo headphone cable (with its 3.5mm jack) to the adapter harness. (Hoping that voltage levels are compatible, of course)

What I need is the pin-out for the CD player connector so I can match up L+, L-, R+ and R- (and ground, if used). I've done some Google searching and only found one image from a sort of sketchy looking site in Russia. I do have a simple multimeter and basic electronic/electrical skills if there's a way to 'test it out' myself.

Thanks in advance for info or referral to knowledgeable folks.

[Imagery]

I believe that you'll be wiring a three conductor system. You should have a L+ and R+ and a common ground wire.

[lordbear]

Thanks for your input. I'll keep that in mind as I go forward.

I admit I'd be surprised to discover that what you describe is the case. Every implementation of (stereo) audio signals I've encountered required + and - lines for each channel. I suspect this has to do with an analog signal carried over a DC voltage, with the opposing polarities allowing for pushing up and pulling down voltage levels across 0 volts. A common signal ground would make stereo into mono, I would think. *shrug*


I believe that you'll be wiring a three conductor system. You should have a L+ and R+ and a common ground wire.

["Mad" Miles]

The installation techs at Best Buy are quick and know what they're doing. I once installed a car stereo in a Toyota Mini-Pickup, and what took me hours, takes them minutes.

If you have $30-$50 for their labor (my rough guess from vague memory, you might want to call and ask) I highly recommend them

I've bought two upgrades and had them installed there, with ease and economy.

The second time because someone ripped my previous system while my pony was parked up on Arlington in N. Berkeley back in '09.

[podfish]

Every implementation of (stereo) audio signals I've encountered required + and - lines for each channel. I suspect this has to do with an analog signal carried over a DC voltage, with the opposing polarities allowing for pushing up and pulling down voltage levels across 0 volts. A common signal ground would make stereo into mono, I would think. *shrug* that's not quite what's going on... you're confusing 'analog signal' with 'alternating current'. You're right, the 'analog signal' is based on an analogy of changes in voltage to changes in air pressure.
The voltage difference between the two wires at a given speaker is used to drive its motion. If one of the wires is also used as a reference for a third wire, the difference between it and that third wire can drive the other speaker. If that common wire is attached to the chassis of the amplifier (and the car), it's also a 'ground'. As far as I know, the +/- convention on speakers is only used because people are used to seeing it on batteries. It's used to keep the speakers in phase (pushing out or pulling back). Only if the coil wire had another path back to the amplifier (was 'grounded') would it matter.