no power to ecm, ecm fuse, fuel pump won't buzz for the initial 3 secs, no start....

Discussion in 'Chevy Truck Forum' started by Chevy94k1500, Apr 26, 2015.

  1. Chevy94k1500

    Chevy94k1500 Full Member

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    Ok, so. ... I just got through chasing down a short on my brakelights. FINALLY found it. As I got it all put back together n went to go start up the truck realized I don't have any power to my Ecm fuse, ecm, fuel pump isn't getting the initial 3 sec priming signal from the ecm. Initially thought it was pump until I jump the orange battery feed wire to the gray load wire and heard the fuel pump start to buzz... anybody have any ideas on what I can check? I'm really hoping my ECM isn't fried... oh another thing. .. when I go to start up the truck. I get no check engine light or anything upon turning the key? Any clue? Thanks for any info..
     
  2. chevychase

    chevychase Semi-Admin
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    Okie dokie...what has power with key on? Does gauges work? The courtesy fuse/ctsy is for the check light.
    When you turn key to on green/white wire at relay should get 12 volts for a few seconds..tell me what works key on.
    I will be back in a few.
     
  3. Chevy94k1500

    Chevy94k1500 Full Member

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    I knew we had a connection somewhere. I missed you too buddy! Lol ok... orange wire on relay has 12 volts. Relay is getting nothing on the green/white wire. Fuses that are hot all the time are ctsy fuse, park fuse, stop fuse and battery fuse.
    With key on I've got 4 wheel drive fuse, brake fuse, stop fuse, ctsy fuse, htr-AC fuse, frt wpr fuse ,ignition fuse, and battery fuse....
    ecm is getting the battery feed from the orange wire straight off the junction block. Same orange wire that goes into relay. Some posibilties that come to mind are my neutral safety switch? Ignition switch, fried ecu, or just a fried fusible link? I know I can jump the relay n hear it click, I've got 4 relay behind the glove box two of the four I hear clicking. Not sure which relay goes to what on those ones though? Thanks again... MUCH appreciated!
     
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  4. Chevy94k1500

    Chevy94k1500 Full Member

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    Just to give you an idea 20150416_202548.jpg
     
  5. chevychase

    chevychase Semi-Admin
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    I will help later .they just called taken my mom to the hospital....if all okay i will be back later.
    So your saying only fuse with no power is the ecm fuse.
    Look theses over click here look this over also here

    this you will see color code and what link goes to each circuits

    [​IMG]

    [​IMG]
     
  6. Chevy94k1500

    Chevy94k1500 Full Member

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    Thank you! Hope all is ok...
     
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  7. chevychase

    chevychase Semi-Admin
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    She/mom was dehydrated bad..stupid doctors has her on coumadin blood thinner..she was bad.
    The relays behind glove box for heater/ac .



    This will same me having to type all the troubleshooting no power to ecm fuse ...and no check engine light...click here

    Need futher assistance ask..
     
  8. chevychase

    chevychase Semi-Admin
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    When you get to link click on view full answer..if assistance pops up..just click him off...redneck assistance people lol
     
  9. Chevy94k1500

    Chevy94k1500 Full Member

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    Ok.... so basicly I've just got to test what is stated on that last post in that forum then? But that was with him having power to the ecm and inj fuses and I do not. I've went through wuth a continuity tester and tested continuity from brakelight switch, to ecm fuse, to gauge... all are connected. All are pink with black stripe. But where should the actual power source be coming from with key on?
     
  10. chevychase

    chevychase Semi-Admin
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    Ignition switch powers these..when key turned on green white wire should have 12 volts for a few...his was injectors...and no power to ecm fuse as yours.
    Read all in the link ..at bottom has charts how too. All your truck is powered by the fuse links. ..ignition...lights..all are.
    No light no 12 voltas at green/white wire might be the ecm..hope not. Injection wire/ecm inj A&b is pink/black also ecm.
    Both gets power when key turned on ..ecm will get power from fuse link..and relay..you have power there.
    Some reason you are not getting command for start up green/white wire? usually ..a bad fuse..ecm..or flaky ignition switch.
    When you turn key on should have power at pink/black wires..or start.
    Here is a better diagram to look over. the dlc..is where you scan in diagram below..the other diagram i left shows a fuel module..you will not have this.
    for a 7.4/454 engine. In that diagram pink..will go to orange at relay...to start. Hard to explain all this..hope you get what i,am saying.
    Just look this diagram over good. pcm..is ecm..try this also see if service light comes on jumper A & B at scan port with key on...check ctsy fuse is good.
    [​IMG]
     

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