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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: bbrixey on October 21, 2013, 07:41:54 am
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Hello all,
I have a 76 K20 4x4. Bought it a few months back and have had NO issues with it. Hop in and start her right up. Well, got in over the weekend, started her up and got about a mile from the house. With no warning, everything shut off, motor, lights. I have nothing. I got it pulled over and sat there for a second. Turned the key and got nothing. No click, no lights, deader then a door nail.
Got her towed home, checked battery, it was fine. Still a good charge. Took alternator off and took to local parts store, That was fine. FIgured with a good battery and a possible dead alternator, I should at least get something.
Went ahead and checked fuses even though didn't think that would have anything to do with it. I blown fuse and that was the radio. When I bought it the ole farmer told me the radio didn't work, figured it was the fuse, just never bothered looking yet. Followed wiring and didn't visually see anything to be shorted out.
Anyone have any ideas?
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Take your battery cables off, clean and reinstall.
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There was no corrison on the terminals and they where tight. I did check that also. But did not check where negative went to frame or positive to starter. Will check that this evening. Will go ahead and remove from battery and visually check both cables. Right now, just scratching my head.
Thanks
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Sounds to me like one of the fusible links at the starter. A fusible link is basically a thinner piece of wire, so if you have a short somewhere, instead of burning up your wiring harness, you burn this short piece of thinner wire out where you can get at it easily. What you are describing would result from a blown fusible link. Why did the fusible link blow? The insulation to the frame could have work through on one of the big wires that supply major systems on your truck, so it contacted the frame and burned the link up.
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I'd go with rich weyand on this one, sounds like fusible link burned through. Like he stated, there is one at the starter, but normally on these trucks there is one on the firewall terminal above the engine on the left side near the power brake booster where the hot leads come together also. Mine burned there a couple of weeks ago after shutting the truck off. Came back to start it, and had no power anywhere. Mine ended up being caused by a bad component in AC system. Good luck.
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so how did the wires look at the starter?
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Well, I have power to the starter solenoid and coming off the solenoid. I tested just past the fuseable link next to the starter and still had power. Tested at the alternator with the ignition on and off and no power.
Took the wires off the alternator and tested same as above, no power. Have not checked the fuseable link at the firewall yet. Need to get a step stool to get to that. lol. Not as young as I once was.
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not real familer with the electric on our trucks but do you have any power at the fuse box?
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Don't mean to thread jack, but I've run into the same problem.
Was just pulling out of the driveway and my radio shut off and flashed back on, as well as my led lights under my dash and heard a bunch of spark noises and then poof, nothing. The radio was also turning on and off during idle when I started the truck up and after I did it I shut it off and turned it back on and was fine, but the second I revved the engine to pull out of my driveway is when the truck lost power.
Towed it home and poped the hood, the negative battery terminal was smoking. No power at the battery with a test light. The battery and positive terminal were very hot. The fusible links at the starter appear to be good, same with the fusible link at the junction block next to the brake booster. Checked ign fuses and all other ones under the dash and they appear to be good. No visable wires that I can see have been burned through.
Pulled the battery out and there is power in the battery.
And help ASAP is very appreciated as I need my truck for work tomorrow and don't have room for down time or a spare vehicle.
Also then only things I have done to the truck recently are an oil change, thermostat change and radiator flush.
-nic
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You have a short somewhere that is pulling beaucoup current from the battery. The only way the terminals get hot enought to smoke is if there is resistance at the terminal connection and there is a lot of current through it. For it to still be smoking once it was towed, that current continued flowing even with it off. I think there is a short in one of the battery wires to the starter or the alternator, which is before the fusible links. Check integrity of the battery cables. You are looking for rub-through of the insulation where the wire rubs on the frame or the alternator bracket or a cable holder. The reason it started doing it when you started the engine, then stopped, then started again when you revved the engine is that the engine vibration or leaning over on the mounts under revving wiggled the wire where the short is and made the connection, then it fused in place from the arcing.
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You got it rich, was the + cable to the starter. Rubbed through next to the fuel pump on the frame. I'm so glad it wasn't something worse. I'd be a shame to park my truck for the winter just after we finished everything on it, thanks again rich! 8)
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No problem. That was an easy one!