Head unit only powering when lights are turned on.

Discussion in 'GM Electrical Tech' started by protwizz, Jul 4, 2010.

  1. protwizz

    protwizz New Member

    I've just installed a Pioneer Double Din AVH-3200BT head unit in my 2010 Silverado, but I'm only getting power when the lights are switched on. There are only 3 wires other than the speaker wires and ground coming out of the dash. One is 16 Gauge and Red with a white stripe. One is 18 Gauge and solid yellow. the last is 18 Gauge and solid Dark Green. Every wiring diagram I've found for a Silverado list an orange wire as being the constant 12v +, but since I didn't have that I connected the Red/White wire. Could this be my problem?
  2. jordanr1987

    jordanr1987 Rockstar

    im in the middle of installing my satellite radio and i dont think the orange is what you want
    on my 03 silverado orange(pin #13) i tapped the power from the sirius unit to this and even when the car is off the satellite will still stay on
  3. Springthing

    Springthing Epic Member 5+ Years 1000 Posts


    It sounds as though you've connected to the wrong wire. I would suggest a voltmeter to check which wires do what. For some reasons wiring diagrams are often off their mark and don't necessarily reflect what you have in actuality. Sometimes the wires will be a different colour or, like in your case, missing altogether.

    Where did you purchase your head unit? Along with the head unit you should have purchased a wiring harness. They are normally under $20 (unless in special cases where they are over a hundred) and some places will even send you an install kit that includes a wiring harness. The wiring harness will be specific to your vehicle and the only wire colours you then need to match up are the colours of the wires on the wiring harness (which then plugs into your stock radio plug/harness) and the wires from the diagram that come with the new head unit.

    Barring that, to help with your immediate problem, I would say hook the wires up to a voltmeter and see what has constant power, what has power when the accessories switch is on, and which has power when the lights are on.

    Constant on makes sure all your presets and clock functions are saved.
    Accessories turns the radio on and off along with every accessory in your truck, so when you switch the key on in the ignition.
    Light power is used, different in different head units, to either dim the display at night, illuminate the buttons/faceplate, or can be totally absent in some cases.

    An inexpensive voltmeter can be had for $10 or so. Checking your wiring will only take a minute or two.

    Good luck!

    ---------- Post added at 12:04 PM ---------- Previous post was at 11:50 AM ----------

    Here is a link to a site that has the harness(es) you'd need, depending on the stock equipment you are trying to replace. Onstar, Bluetooth, steering wheel buttons, etc etc.
  4. DangerousDane

    DangerousDane New Member

    Your truck needs a kit for a radio installation that keeps the door buzzer working and the radio and windows working after you turn the key off but before you open the door to get out. The constant and ign wires don't even go behind the radio. Becareful with the purple wire that runs the airbags/ if you don't install the kit. You can't leave it bare or you might pop the airbag at an other than convienient time. I believe its a negative pulse thru various resistances to run many different things in the truck on just 1 wire.
    The only other way to get the constant and ign wires is at the ign harness where you would hook a remote start alarm up.

    I don't use the kit in my truck because I don't like the door buzzer and it costs $50 or whatever. But you don't want to go playing around with your ign harness unless you can do a good job and not turn it into a big mess.

    BTW you had it hooked up to the illumination or dimmer wire. Be careful the dimmer can roast your radio if you roll the dimmer down on the dash while the radio is hooked to it.
    Last edited: Aug 4, 2010
  5. senorbob999

    senorbob999 New Member

    you dont need a voltmeter or a special harness pug for your truck. they are wastes of money for the simply wire mix up you have. go to this site and you will get a wiring guide for your truck and it will tell you were to wire everything. just look up your year truck and all the info you need is there.

  6. djturnz

    djturnz Member

    Its already been said, but it sounds like you hooked up the dimmer wire to the remote on wire of the radio. The dimmer wire tells the radio when the headlights are on, and it causes the display to dim since it's probably dark. Usually the harness you would buy to attach to the radio so that it plugs into the factory harness has a wiring diagram with it, and you just match it up wire for wire to ther head unit diagram. I have never dealt with the newer GM harness that runs the door chime so it may be different.
  7. Dr Len

    Dr Len Rockstar 100 Posts

    You have to remember that your truck has a CAN Bus system in it You cant just hook up a new head unit without it.
    You have to use an interface to use an aftermarket head unit

    Heres a link to help you
  8. bwhitt86

    bwhitt86 Rockstar

    Unfortunetly you do need a special harness. And you should use a meter. You need a lan harness because there is no accessorie wire at the deck. They have data wires. There are a couple of accessorie wires but their low current you need to use a relay. I haven't seen that harness for 50 bucks, normally bout 100 but if you can find one cheaper more power to ya. You don't want to mess around with the nbs pickups. The radio interfaces with airbags and such sometimes plus you'll loose your chime if you don't use it. Don't even try to mess with it. And whatever you do don't cut the harness off and hardwire it like he's suggesting, not smart. Like i was sayin the only accessories are low current so even if you did hardwire it you'd have to use a relay. You need that harness period you could screw alot of stuff up. And plus even if you could hardwire it don't ever trust what a site tells you as far as stock wire colors. You can use it as a guide but always test them because the wire colors vary alot of times. Always test with a meter if your hardwiring. Its never a sure shot. People think this stuffs easy and a ten year old can do it but the people who say stuff like this obviously don't have any experience in these matters and when they put stuff in they come to people like me and don't talk crap anymore . I've had years of experience and i still run into stuff that blows my mind
  9. Springthing

    Springthing Epic Member 5+ Years 1000 Posts

    bwhitt86 has it hit right on the head. It USED to be that a ten year old could do it, but nowadays there's just so much more to the 'radio', it's not as simple as power, front speakers, rear speakers and you're done.

    Hope your install went well. Should be all done up by now. :)

    bwhitt86, thanks for your great explanations! :great:
  10. bwhitt86

    bwhitt86 Rockstar

    I really appreciate that. Normally people fire back and tell me i don't know what im talkin about an how much more they know than i do. Im a proffesional when it comes to car electronics, i do it for a living and i don't tell a mechanic he doesn't know sqaut when he he's talkin about how to rebuild an engine. Thanks anyway for the feedback its good to know at least one person values it.

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