Aftermarket radio staying on

Discussion in 'Audio + Electronics' started by Lattimer, Jul 20, 2019.

  1. Lattimer

    Lattimer Newbie

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    Having a new and confounding issue with my 1994 Blazer. About 7 months ago I installed a Pioneer touch screen head unit. I have the exact same head unit in another vehicle.

    Occasionally, when I turn the key off, a few seconds later the unit turns back on. If I get out of the truck too quickly I miss it. It's drained the battery on me twice now. If I catch it doing it, I cycle the key on and back off and the radio stays off.

    This is a new issue over the last couple of weeks. Head unit in my other vehicle is exact same model but does not have this issue.

    I know it's wired correctly. I used an adapter harness to the factory wiring. Factory wiring all looks intact, I've had the whole dash out and found very little tampering with the harness.

    So other than something internal to the radio being the culprit, what can I check? Does anyone have a diagram for where the stock wiring originates? Is there a relay in the circuit or anything like that?

    Any help is appreciated
     
  2. df2x4

    df2x4 Domestics only.

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    This really sounds like an internal issue to me. I have identical Pioneer DEH-P880PRS head units in both of my '97s, and one of them has started staying on when I shut the key off in the past couple years. I know it's not a wiring issue as I installed both of them myself and have double checked everything multiple times. My issue is 100% predictable though, if I just turn the unit off before I shut the truck down I get no battery drain or weird behavior. To replace that head unit and all its accessories with a modern unit that has comparable sound quality I'm looking at $1000 or so, which I've been reluctant to spend. In your case I'd see if you have any kind of warranty still available and send your unit back for a replacement if possible.

    The only thing besides an internal radio failure that I can think of would be that maybe your ignition switch is going bad and supplying power to the accessory circuits when it's not supposed to. When the head unit stays on does anything else work? Like power windows for instance?
     
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  3. Lattimer

    Lattimer Newbie

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    No, just the radio stays on. And its odd. It shuts down when the key is turned off and reboots a few seconds later. But only once in a while. If it does it, I cycle the key on and off and it stays off.

    I've seen them just stay on from an internal short, so the memory wire kept the radio on. And I've seen a bad amp backed the remote turn on wire and keep a radio on, but I'm not using that wire, its taped off. This is a new one on me.
     
  4. Jglew82

    Jglew82 I fix stuff

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    That does sound like an internal backfeed on the deck. If it were mine, I'd pull it out and temporarily disconnect the key-on circuit wire when you want to turn it off and see if the power comes back on like it has been doing. That should tell you for sure.
     
  5. upper_tanker

    upper_tanker I'm Awesome

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    I have a Kenwood Excelon single din head unit in my Tahoe that's probably only two years old. Last year, I went to park it one night, turned the key off, and noticed music still playing as I was unloading my stuff out of the back seat. I couldn't figure out WTF the sound was coming from. I finally put my ear next to the door speaker, and I could faintly hear music playing from the radio. I looked up at the faceplate, and it was all blacked out like it was off.

    I put the key back in the ignition, started it up, and the same song was playing. I turned the key back off, and it still played music. I ended up removing my face plate and hitting the reset button on the actual deck, and that solved my problem thus far.
     

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