Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

How in the !@##$ do you find a dead short

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 84CUCV, Aug 16, 2004.

  1. 84CUCV

    84CUCV 3/4 ton status Premium Member

    Joined:
    Jul 1, 2002
    Posts:
    7,115
    Likes Received:
    2
    Location:
    NJ for now
    This a is a PIA! I have been looking all over the truck with no luck. Found some wires with the insulation cooked off, but they are not touching anything. What the heck am I missing? what else could it be?

    thanks mike
     
  2. 1-ton

    1-ton 1/2 ton status Premium Member

    Joined:
    Apr 17, 2004
    Posts:
    2,884
    Likes Received:
    162
    Location:
    Las Vegas, Nevada
    Electrical shorts are like you said PIA! The only advice I can offer you is to invest in a tool that will help you find electrical shorts. A cheap one will cost you any where from $50 to $75, but if you compare the cost of what an automotive electrical specialist will cost you to fix the problem it is a good deal.

    The way they work is that they look like an ordinary test light with an alligator clip that connects to a ground point. These tools have a special circuitry built into the probe handle. When you use the pointed steel tip probe to penetrate a wire, if the little green LCD light on the handle lights up, then there is no short on that wire; but if the little red LCD light lights up, then that wire has a short on it.

    Once you find the wire with a short in it, then you have to trace the wire to see if you can visually see where it is either grounded or cross-circuited to another hot wire.
     
  3. trikstark5

    trikstark5 1/2 ton status

    Joined:
    Feb 17, 2004
    Posts:
    169
    Likes Received:
    0
    Location:
    usa
    Have you isolated so what circuit is creating the problem, for example: a short in the stereo system? Once you have isolated what ciruit has the problem, then it is just a matter of isolating all the wires that run into that ciruit. A DVM will help isolate the short. Hope that helps, don't remember reading what the actual problem is though.
     
  4. 84CUCV

    84CUCV 3/4 ton status Premium Member

    Joined:
    Jul 1, 2002
    Posts:
    7,115
    Likes Received:
    2
    Location:
    NJ for now
    The first time I started my k5 back up after soldering some wires. It started then just shut off. tried cranking and smoke cam from the batteries. Nothing cranking after that. was fine before I did the work. Man, this sucks. I will be going to the store to find one of those probes. thanks mike
     
  5. trikstark5

    trikstark5 1/2 ton status

    Joined:
    Feb 17, 2004
    Posts:
    169
    Likes Received:
    0
    Location:
    usa
    What wires did you solder together? Did you put shrink wrap or electrical tape around the solder connection? Are you sure the wires that you solder together are actually suppose to be together? /forums/images/graemlins/dunno.gif
     
  6. 84CUCV

    84CUCV 3/4 ton status Premium Member

    Joined:
    Jul 1, 2002
    Posts:
    7,115
    Likes Received:
    2
    Location:
    NJ for now
    The truck is right from the government. It came with the ends for the two alts cut, so I got ends and soldered it up, with my other m1009 as a diagram. Its done right, unless my wiring is messed up on my other m1009. After soldering I put liquid electrical tape on. Any other ideas?? thanks


    mike
     
  7. 84CUCV

    84CUCV 3/4 ton status Premium Member

    Joined:
    Jul 1, 2002
    Posts:
    7,115
    Likes Received:
    2
    Location:
    NJ for now
    Could a fried relay have anything to do with it??
     
  8. justinf

    justinf 1/2 ton status

    Joined:
    Sep 23, 2003
    Posts:
    684
    Likes Received:
    0
    Location:
    Tuscola, Illinois
    Yes, it could. If the relay burned up, it could be shorted to ground.
     
  9. 84CUCV

    84CUCV 3/4 ton status Premium Member

    Joined:
    Jul 1, 2002
    Posts:
    7,115
    Likes Received:
    2
    Location:
    NJ for now
    That might be in. thanks
     
  10. txtough

    txtough Registered Member

    Joined:
    Aug 31, 2003
    Posts:
    39
    Likes Received:
    0
    Location:
    Lubbock Texas USA
    Here is a cheap trick that will work through carpet and walls and anywhere you can get within 4-5 inches of the harness. This only works with a dead short.

    1. Go to the local auto parts store and get a circuit breaker that will go in the same place as the fuse that is blowing. If you can find it a "fast trip" breaker works better.

    2. Go to walmart and get a cheap compass in the camping department.

    3. Install the circuit breaker in place of the fuse. As it trips and resets the point where the circuit is shorted will make a magnetic feild that will collapse every time the breaker trips.

    4. Trace over the path of the harness with the compass and look for the needle to jump when you get near the short while the breaker trips.
     
  11. trikstark5

    trikstark5 1/2 ton status

    Joined:
    Feb 17, 2004
    Posts:
    169
    Likes Received:
    0
    Location:
    usa
    I fried relay could definitely be the problem, what caused the relay to fry? If you don't find what caused the problem, when you put a new one in, it is just going to fry again. I would isolate everything and confirm my connections again. Make sure they are not hitting ground anywhere.
     
  12. 84CUCV

    84CUCV 3/4 ton status Premium Member

    Joined:
    Jul 1, 2002
    Posts:
    7,115
    Likes Received:
    2
    Location:
    NJ for now
    thanks mike
     
  13. Blue85

    Blue85 Troll Premium Member

    Joined:
    Jul 26, 2000
    Posts:
    9,081
    Likes Received:
    486
    Location:
    Grand Rapids area
    [ QUOTE ]
    The truck is right from the government. It came with the ends for the two alts cut, so I got ends and soldered it up, with my other m1009 as a diagram. Its done right, unless my wiring is messed up on my other m1009. After soldering I put liquid electrical tape on.

    [/ QUOTE ] Is this a 24V dual alternator setup? If so, you have to keep one of the alts floating from chassis. If somehow you tied the two in parallel, it could be a direct short.

    What fuses are blowing? What wires are melted?
     
  14. 84CUCV

    84CUCV 3/4 ton status Premium Member

    Joined:
    Jul 1, 2002
    Posts:
    7,115
    Likes Received:
    2
    Location:
    NJ for now
    Yea, its a 24V dual alternator setup. That cant be it the alts are not hooked up yet. No fuses are blowing. The blue wire up by the relay melted.

    mike
     

Share This Page