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Electrical problem - blew something - FIXED

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Panther, Feb 26, 2002.

  1. Panther

    Panther 1/2 ton status

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    Hey guys. Here's my problem...

    I finally got around to hosing off the blazer after my last debacle, I mean wheelin trip [​IMG]. I managed to clean out the back end really well since it was warm outside.

    However when I got back in the truck and turned the key, there was nothing. The interior light, headlights, and horn all work. However, I get nothing from the ignition. I don't even get the dash to light up (to test) when I turn the key.

    Of course the first thing I did was check the fuse box. I pulled every fuse and they're fine. My best lead is that it has trailer wiring that I wacked real good a couple of wheelin trips ago. I'm guessing I shorted out the trailer wiring by spraying out the back end and then turning the key.

    Is there a fuse/relay somewhere between the battery and fuse box or between the fuse box and ignition where the trailer wiring would be spliced in? I checked my manual and it says trailer wiring is not factory installed and therefore is pretty ambiguious. All it says is it should be spliced into a line from the battery. Any ideas on where to look or should I just start tracing back from the battery?

    Thanks everybody. And just for irony's sake, as I was spraying it down, I said to myself, "You know you really need to get in there and cap off that trailer wiring before you short something" [​IMG]. Oh well.

    UPDATE
    ------------
    OK, I got to check some stuff on the truck last nite and wanted to repost.

    I traced the trailer wiring up to the engine compartment and found where it spliced to the battery. The in line fuse for the trailer wiring was fine (as was suggested to me originally, d'oh).

    What I was able to find was that all the fuses in the fuse box that run off the battery (lights, horn, etc) are getting the normal 12.x volts. None of the other fuses (the ignition switched ones) are getting more than a few tenths of a volt regardless of how the key is turned. I also found that the starter is getting a full 12.x volts.

    So I started flipping through my manual and the best lead I can find is the "engine control switch". It is apparently connected to the distributor, starter, and alternator. Does anyone know where I can find it? One diagram I found puts it behind the "bulkhead connector". Does that mean the ECS is in the cab (behind the firewall)? Once I find it, I can troubleshoot it and fix it or move on.

    Thanks again everybody.<P ID="edit"><FONT class="small">Edited by Panther on 03/01/02 07:38 AM.</FONT></P>
     
  2. 87GMC

    87GMC 1/2 ton status

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    Re: Electrical problem - blew something

    I didn't think the trailer wiring would be enough to cause a starting problem. Try this, turn on you headlights and turn the key. If the lights stay bright, the signal isn't getting to the starter. Check you ignition switch and your solonoid wiring. If the lights dim, the starter is getting the signal. Check the starter and solonoid itself. Also check you battery wire connections. If they are dirty or loose they will pass enough amps to run you lights but won't sustain the amps needed to turn the starter.
     
  3. Panther

    Panther 1/2 ton status

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    Re: Electrical problem - blew something

    I can (almost certainly) guarantee the starter is not getting the signal. There is no response when I turn the ignition key (back or forwards). No radio, no dash lights, no fuel pump. There's no change when I turn the key further to start either. No hum or even click.

    It was starting fine before I washed it so I don't think it's loose/dirty wires. I am pretty sure the trailer harness is not run from the fuse box and I'm thinking the fuse "at" the splice has blown.

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     
  4. chevyracing

    chevyracing 1/2 ton status

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    Re: Electrical problem - blew something

    fuseable link is toasted. Replace it and be merry.
    John

    Like to go sloppin' 'round in da mud in a rapid fashion....=)

    <a target="_blank" href=http://coloradok5.com/gallery/albun31?&page=1>BLAZER PICS</a>
     
  5. shawnboy

    shawnboy 1/2 ton status

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    Re: Electrical problem - blew something

    You are correct sir!
    Shawnboy.

    <font color=red>If you are having too much fun it's probably illegal.</font color=red>
    <font color=red>Because I, Am, Canadian!!!</font color=red>
     
  6. Stoopalini

    Stoopalini 1/2 ton status

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    Re: Electrical problem - blew something

    I third that one ..... most likely a fusable link.

    Thomas.

    -- '84 1-Ton Blazer --
    When the goin' gets tough,
    the tough go 1-Ton [​IMG]
     
  7. Panther

    Panther 1/2 ton status

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    Re: Electrical problem - blew something - UPDATE

    TTT (please check the update above)

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     
  8. Blazer79

    Blazer79 1/2 ton status

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    Re: Electrical problem - blew something - UPDATE

    Sounds like the transmission is not in Park. I'm assumming you did check that, so I'll say it could be the safety switch in the steering column is bad. You can also try "playing" with the tranny shifter to see if it activates the switch.

    Hope this helps.

    <font color=purple>//////
    <a target="_blank" href=http://blazer79.freeyellow.com>blazer79.freeyellow.com</a></font color=purple><font color=black>
    Soon a 454 K5!!</font color=black>
    [​IMG]
     
  9. Panther

    Panther 1/2 ton status

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    Re: Electrical problem - blew something - UPDATE

    I will try that tonite, but I would think I would still get power when I turn the key (for radio, dash, etc) even if I was not in Park.

    I've found some leads in the message archives, mostly fusable links/wires from the starter to ignition. I will keep you guys updated.

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     
  10. m j

    m j 1/2 ton status

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    Re: Electrical problem - blew something - UPDATE

    so did you check the ignition switch?
    on top of the steering column

    formerly 77chev
    still a jerk though
     
  11. Panther

    Panther 1/2 ton status

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    Re: Electrical problem - blew something - UPDATE

    No that's on my list for tonite.

    What's the easiest way to check it? I assume there are two wires at the base of the steering column that I can check!?


    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     
  12. m j

    m j 1/2 ton status

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    Re: Electrical problem - blew something - UPDATE

    which K5? 90 or old one?

    formerly 77chev
    still a jerk though
     
  13. Panther

    Panther 1/2 ton status

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    Re: Electrical problem - blew something - UPDATE 2

    My fault. Its on the 90.

    Another update. I was trying to trace the wires from the starter last nite. I traced them around the back of the engine compartment and must be on to something. After that, the dash lit up when I turned the key forward. But when I tried to turn it over, it all died again. So I think I am looking at a bad connection somewhere.

    Anyone know where the two wires off the smaller screw on the starter go? It is a fairly large, red wire and a smaller purple one. My manual shows they both run to the "engine control switch" through the "bulkhead connector". Is that just the ignition switch up in the column?

    Thanks much.

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: Electrical problem - blew something - UPDATE 2

    The red wires (at least in the mid 80's) off the starter (one into two with two fusible links I think) go up the firewall, and meet up at a "junction" block on the firewall (engine bay side) that is up near the cowl, kind of above the distributor, towards the drivers side. From there, they go into the firewall connector, which is obviously the back side of the fuse panel.

    The purple wire, IIRC, goes straight from the starter to the firewall connector, nothing else connected to it in the engine bay.

    If I were you, I'd first check to see if there are TWO red wires going to, and coming off the "junction block" I mentioned earlier. If there are, I'd check continuity from the red wire at the starter to both of those AT the junction block. While checking continuity, jiggle the wires between the starter and the junction block. Fusible links can be "bad" but still conduct sometimes, at least enough to leave you guessing.

    If you eliminate engine bay wiring (the two fusible links) then its time to focus elsewhere.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  15. Panther

    Panther 1/2 ton status

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    Re: Electrical problem - blew something - UPDATE 2

    OK, I've think I've encountered the "junction block". There is a piece of metal (with two screws for eye connectors) mounted on the firewall with several hot wires running in and out. I will check all those wires.

    I will also try to trace the entire purple wire from starter to firewall (fuse box entry) and also check it for continuity.

    Thanks Dorian.

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     
  16. Stoopalini

    Stoopalini 1/2 ton status

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    Re: Electrical problem - blew something - UPDATE 2

    This really sounds like the "text-book" fusable link gone bad problem. The intermittent nature, the systems affected, etc ... I would recommend you just replace the fusable links down at the starter, and I bet your problem goes away.

    On my Camaro, I replaced all of those fusable links with weather-resistant fuse holders. This way, if they blow again, I can just replace a fuse instead of cutting out and resoldering in a new link.

    Good luck,

    Thomas.

    -- '84 1-Ton Blazer --
    When the goin' gets tough,
    the tough go 1-Ton [​IMG]
     
  17. BlazinRojo

    BlazinRojo 1/2 ton status

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    Re: Electrical problem - blew something - UPDATE

    i'll bet dollars to pesos its a fusible link. replace it and every should light up again

    I can get us out of this, but its gonna take a whole lot a flooring! - Homer Simpson
     
  18. Panther

    Panther 1/2 ton status

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    Well it's fixed and you guys are gonna kill me.

    While checking the junction block on the firewall (in the process of tracing wires from the starter), I noticed I was getting intermittent voltage (12, 4, 0, 12, 0, etc) there. When I tugged on the wire from the starter, I would get the dash to light up, but it would die if I tried to turn it over.

    During my "trials", I had left the ignition on (key turned forward) and I went under to check the voltage at the hot terminal on the starter. It seemed fine, but when I dragged the probe across the eye connectors, I saw a spark and I heard the radio go on. So I wiggled the hot wire running from the starter and everything stayed on. So I unhooked the battery, pulled the two wires off that terminal, cleaned it up and screwed it down real tight. And everything worked fine.

    Thanks a lot for all the help guys. I guess the lesson here is KISS and never assume anything is working until you fully test it.

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     

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