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Electrical Problems...

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by az-k5, Jan 25, 2004.

  1. az-k5

    az-k5 1/2 ton status

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    Okay, I put a fancy new 140 amp alternator in, got my bumper modified (thanx Harley) to fit my new winch, hooked everything up and ran into a problem. Whild dragging Harley's K5 to stretch my new cable I started to smoke one of the stock underhood wires. This is the wire that goes from the resistor on the firewall to the back bolt in the alternator, it is a 10ga red wire. It links to another 10ga red wire (goes to the starter) just before it goes into the resistor. This is the factory wiring still. I wonder if I need new wires, heavy'er gauge, or bypass the splice and give each wire it's own lead to the resistor, or maybe a combo of them? This happened twice but only when I had a good load on the winch, and it would work fine after about a minute of "truck is off" time. I also have new battery cables (1 week old, 2ga).
    Any help is great help as I hate electrical /forums/images/graemlins/angryfire.gif.
    Thanx /forums/images/graemlins/ears.gif
     
  2. Confedneck

    Confedneck 3/4 ton status

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    i would go to a higher gage wire, maybe 6ga or even 4..
     
  3. HarryH3

    HarryH3 1 ton status Author

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    That 140 amp alternator puts out WAY more current than your 10 gauge wire can handle. When you had the electrical system loaded down with the winch then the alternator started doing its thing, making lots of current. /forums/images/graemlins/cool.gif But since the wire from the alternator to the battery is too small, it turned into a heating element. /forums/images/graemlins/eek.gif You need some beefy wire coming off the back of that bad boy to carry the load. 6 gauge is probably enough, but with 4 gauge I doubt that you would ever have to worry about it for sure. /forums/images/graemlins/thumb.gif
     
  4. therobzilla

    therobzilla 1/2 ton status

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    Matt,

    Use 2Ga for the hookup, it takes away the issues, like Harry said, 140 amps thru 10 gauge is not the way to go. Get some big dog either 2 ga or 4 ga wire from alternator to hookup. Mine puts out 200 amps and I run 2 gauge adn even some 00 GA, and some 4Ga in other areas. The winch really works over the alternators and batteries.

    Rob
     
  5. Hossbaby50

    Hossbaby50 3/4 ton status

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    Hey Rob,

    Do you need to upgrade the alternator wire size if you are running a stock alt and a winch? I am running the stock at with my Warn 12K. I know I need more alternator but that will have to wait a little while. I will let the winch suck the Optima down some if I have too. THank

    Harley
     
  6. az-k5

    az-k5 1/2 ton status

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    Okay so I hate wires. Let me make sure I have this correct.

    I will run a 4ga from the bolt on the back of the alternator to the black resistor thing on the fire wall, then from that same resistor I will run some more 4ga down to the starter (+) bolt, then hook my regular 4ga battery cable up to that as usaul and back to my battery goes my 140 amps of recharge juice? I hope so. What other wires should I upgrade soon?
    Thanx
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Any reason why this 4 gauge wire can't run straight to the battery?
     
  8. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

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    I was thinking the same thing. Your alternator should be tied directly to the battery if possible. You could be losing out over all those connections. Leave the small factory wire where it is and run another heavier wire right to the battery. Or you could run a heavier wire right to the winch where your battery cable is connected to the winch. Electrically its the same as hooking it to the battery except its hooked directly to the winch so your alternator can apply full juice to the winch and Your battery will still charge.
     
  9. az-k5

    az-k5 1/2 ton status

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    I would really like to run the wire from the back of the alternator strait to the battery and just not worry about the other wires. That would be alot easier for sure. Can it work this way?
    Thanx for the help so far everybody.
     
  10. BobK

    BobK 1/2 ton status

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    If it's a orig GM 3 wire alt. you can't go directly to the battery.
    You need a wire that will tell the alt to start charging.That's the #2 terminal on top of the alt.(10SI +12SI alts).
    If you want to you can run a 2 gauge wire from the charge termianl on the alt to the battery but just put a small jumper from the #2 terminal to the charge terminal.This will "excite" the alt. and get it charging.

    I would not recommend this if you have fuel injection,big stereo's,or even a moderate amount of electonic equip. on your truck.
    The 3 wire system allows the charging system to compensate for increased electical(amps) demand.

    By going directly to the battery with you defeat that system and will suffer from poor charging performance.

    The alt. will only put out 14.2 volts no matter what the demand is.With muliple pheripherals on the amount of voltage to each will be limited,resulting in poor performance.
    In the case of an electric fuel pump that would be bad.

    The 3 wire system will compensate for an increase demand in voltage.Normally the #2 terminal wire takes a reading from a power distibution point in the wire harness.If the voltage draw is increased it will tell the alt to pump up the output.This make the ideal 14.2 volts(approx.) available to ALL the circuits that are on.

    Hope that made sense /forums/images/graemlins/grin.gif
     

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