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so I left my lights on all night in my bronco (1980, 5.8L 6 inch lift on 35's) so the battery died. my brother picked me up from work that day and came to help me jump it. we hooked the cables up turned on his car. after a bit I tried to turn on the bronco. it almost turned over but then made the awful sound you get when you keep trying to turn the key in the ignition after the car has started. I turned the car off but the starter kept trying to start the bronco even after I took the keys out. we disconnected the jumper cables and the bronco stopped. but now there is no power at all, the lights don't turn on, no radio, nothing. the starter used to just keep going a year ago but the mechanic found some faulty wiring and it hasn't happened since. I think I checked all the fuses none are blown are there any fuses under the hood? what do I do next? I'm supposed to get a bunch of snow tomorrow and I would like to avoid the mini van. if anyone has any suggestions I'd greatly appreciate them
 

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sounds like you may have welded the starter fender relay together from low voltage/high amperage

if voltage is low.starter may spin but not throw starter into ring gear,just buzz away on edge of teeth

doesn't say where you are from but if lights were left on all night,battery will be good and dead,and if cold out,maybe junk now if it froze.

the reason you have no power is most likely just from the dead battery

you will need one hell of a good set of cables (probably zero gauge or bigger) to have enough current to start your rig with a completely flat battery
the rig used to jump start will be putting out max amps just to try to charge your battery and then tryng to pull another couplehundred amps to start your truck is asking a lot

I would try charging it with a charger over night and install it and NEVER try to charge a frozen battery with a charger or in your car


even if you did start your rig, you may have wasted the alternator trying to charge a completely dead battery,they are not meant to charge a dead battery,just maintain it and supply power for electrical load/accessories
 

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Discussion Starter #3
thank you so much! before i tried jumping there was still enough juice for the engine to crank just not start. as far as it being cold 40 degrees or so. so i don't know about frozen. i'll wait till after Christmas and take the battery to autozone or something and have them test it. thank you
 

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It could also be your starter solenoid. I had one fail in my 79 Bronco. It would keep turning the engine over without the key. It's the same as crossing the two posts with a screwdriver.
 

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It sounds like the solenoid (Starter relay) on the fender is stuck. It sends power to the starter when you turn the key to Start. If it was stuck on while you were jumping the truck, it is probably still stuck on, sending whatever small amount of power was left in the battery to the starter. With that going on you should expect to have no power for lights or anything else. When you have a problem where the starter keeps going you have to disconnect the battery or the starter will continue to draw.

Try the following to confirm:
  • Disconnect the battery & charge it up while it is disconnected from the truck.
  • Confirm that the battery is charged & shows 12v. If not, replace the battery.
  • Before reconnecting the charged battery, disconnect the large cable to the starter from the solenoid.
  • Connect the battery & measure for voltage at the large solenoid post for the cable to the starter with thh key off.
    • If there is 12v there, disconnect the small wire to the "S" post on the solenoid.
    • Measure voltage again at the large solenoid post for the starter. If 12v is still present replace the solenoid.
  • If you find something different on those measurements, let us know & we'll continue down other paths.

I think an 80 would still use this style of 4 post solenoid.
 

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*if the battery is too low of voltage most automatic chargers won't see it and bring it up, I want to say the Battery Tender needs to see at least 7.5 volts before it will work.
 
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