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Eletrical Problem

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Nate87k5, Aug 12, 2002.

  1. Nate87k5

    Nate87k5 Registered Member

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    Here is my problem: If I try to honk the horn I get a buzzing noise coming from the relay switch. I replaced the horn
    relay switch to find that it is still doing it. Also when I am pressing the horn went the driver door is open I get nothing.
    no buzzing no nothing. I also noticed that the door light under the glove box flickers on when I press the horn when
    the door is closed. Also the radio cuts off when I open the driver door and I have to reset all of the settings. The two
    dome light are not working at all. Any thoughts? Thanks

    87k5
     
  2. Blazer79

    Blazer79 1/2 ton status

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    /forums/images/icons/shocked.gif Run! Get a young priest and an old priest before the steering wheel starts spinning on its own! /forums/images/icons/wink.gif

    Now, seriously, it sounds like your wires are really messed up. I'd consider a new harness kit from Painless or some other company.
     
  3. Sandman

    Sandman 3/4 ton status Author

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    This is strange but it sounds like you have your horn wire connected to the door light switch in the door jam. The first thing that I would check is the wiring on the radio. I've seen people tap in to all kinds of crazy sources for power. Your going to have to get under the dash and start chasing wires. Good luck.
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    As has been mentioned, get under the dash, and remove all the hokey wiring from previous owners. Tape, solder and/or shrink wrap all connections that have been tampered with. If the wires been cut, solder and shrink wrap it.

    This is why you don't cut factory wires.

    Of course, it could be something like a wire grounding out or something, however, I'm not sure that radio memory should die.

    Radio memory/clock (if it was a stock digital radio) door switches (for interior lighting) interior lights, and horn ALL have constant power, and probably all feed from the same constant 12V wire. (small orange wire IIRC)
     
  5. Blue85

    Blue85 Troll Premium Member

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    Someone has done some bad wiring? Are any of your fuses blown? Do your parking lights or anythign else on the truck not work? I ask becasue the dome lights are tied to +12 all the time and the door switches provide a ground path. But the upper and lower interior lights are tied together at the light switch. So if you blow the parking/dash light fuse and turn on the headlights, the upper light and lower lights are powered in series, so you just get some on really dim. Exactly what happens depends on the wattage of each bulb.

    If all of that is OK, it sounds like power for the horn and radio have been tied into the dome light circuit. As I mentioned before, the dome lights get +12V and without any ground path, there is no current through the bulbs and no voltage drop through them, so even the switched side "looks" like a power source to a test light or voltmeter. Someone without much knowhow could have tied into a source like this to power stuff. The clock wire of the radio is such low current that it can get enough voltage from the "low side" of a bulb or other device to work OK. When you open the door, though, the voltage drops to zero and everything is reset.

    First check all of your fuses and then look for wiring that has obviously been redone.
     
  6. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    I know nobody likes wasting money when you could be buying bigger tires etc. But if your wiring harness has been molested by previous owners and emergency repairs . You could start all over with a new wiring harness ( painless wiring comes to mind they use gm color codes etc ) . This is way easier and if you do it yourself. And you'd have piece of mind knowing it works when you need it . Besides you would have an excuse to get under your dash and tighten all those loose screws and stop those annoying rattles.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    I wouldn't worry about a new harness over the 12V constant interior stuff...

    Heck, I've re-soldered EVERY connection on a fuse panel back when I thought I'd never find an un-cut one.

    So far I haven't been impressed with Painless' stuff, at least with their injection stuff...they make troubleshooting more difficult while making the wiring "simpler".

    GM kept a lot of stuff on seperate circuits and fuses, so that when the interior lighting circuit failed, you don't lose ECM power, etc. Painless, from what I've seen, bundles everything they can, together, so if one component fails, you might lose everything...like interior lighting, door locks, etc.

    Again, I haven't closely inspected a Painless fuse panel harness, but if it has less wiring than GM's, its inferior.
     
  8. Nate87k5

    Nate87k5 Registered Member

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    Thanks for all of the advice. Of course I wont be able to really work on the truck until the weekend. I did notice another thing that might give you guys some idea of what it may be. I notice today that power to the cigarette lighter goes out when I open the door. I also noticed that when I try to turn the dome lights on by turning the headlight knob with both doors closed I get the same effect. The horn doesn't buzz the cigarette lighter doesn't work and the radio goes dead. Any new ideas? Thanks.
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    The door switches are prone to failure..they corrode, the wires chafe, etc. Just to save time, I'd pull both of them, disconnect the wires running to them, tape the leads up so they didn't touch ground, and see if you have problems still.

    As bad as these switches corrode, when you pull them, it will be blatantly obvious if they are a problem. You can clean normal corrosion up with some sandpaper, and you can protect them with di-electric grease, but some I've seen corroded beyond fixing.

    It certainly won't hurt to pull them out and make sure they are working correctly though. Just don't let the wiring snake its way back through the hole, or you'll have a fun time trying to get them back out.

    Tape a string (firmly) to the wires if you feel they will go back through, or tape them to the door frame....usually not enough slack to pull them out far enough to keep them from going into the hole on their own.
     

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