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Perplexing Electrical Problem!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by RockBurb, Jul 30, 2001.

  1. RockBurb

    RockBurb 1/2 ton status

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    I have a 1984 Suburban that recently had the alternator start to go bad. The other day I went to start it and it was dead. I have dual batteries (Painless Setup) and flipped over to the auxilary battery and it still wouldnt start. Couldnt jumpstart it either. I finally got the truck started by running a lead off the battery into the S terminal on the starter. Only one problem then. My wipers came on and I couldnt shut them off without removing the fuse. In addition the turn signal lamps in the dash do not blink but come one and stay on. The amp meter and the temp guage fluctuate with the gas pedal as well. ALso the transmission would sometimes shift and sometimes not going down the road (700r4). I found that the fusible link was bad (again happens every few years) and I replaced it, but the problem is still there (the truck does start now). I have a new powermaster alternator to install, and I am crossing my fingers, but am doubtfull that this has anything to do with it (wipers come on with key in acc position). Any thoughts or ideas would be really appreciated!!

    84 Burb with 35's and locked front and rear.
     
  2. prjt_blzr

    prjt_blzr 1/2 ton status

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    The first place that I would start looking is for the chassis ground to the body. You have too many "odd" unrelated things happening for it to be much else.
    Good luck.
     
  3. newyorkin

    newyorkin 1 ton status

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    Wierd!
    It actually sounds to me like a 12-volt hot got pinched together somewhere with your wiper hot, and temp sender wire. The ammeter flux could be actual from bad regulator in the alternator. Maybe for whatever reason, the temp sender wire is picking up the ammeter lead.

    As for the blinkers staying lit, I had that happen in my Camaro when it rained. I replaced a bulb in the taillights, and I think it went away, but I know of other instances where that would be a symptom of a major short somewhere else. Do you have a trailer harness? Maybe someone stuck a paper clip in it or something...

    For the shifting, I don't believe your tranny is at all electrically controlled except for convertor lock-up. I could be wrong about that too though. It would seem odd to have the tranny suddenly go at the same time all this electrical trouble started...

    Just curious, what makes you think the alternator is going bad? I've always found they just went, no real warning. Like on or off, no in-between state. With all these other problems, I'd be suspect that the alternator is fine, and there's some other short somewhere, possibly something to do with the second battery. Did you wire it in series/parallel/isolated?

    I might be wrong here, but I'm pretty sure fusible links really only go bad when they reach thier capacitance, due to shorted out system, they're unaffected by age.
    Here's what I would do:
    Disconnect the batteries and clean off the starter solenoid really well, then all the connections. Reconnect and see if that helped. If not, take out one battery and return to stock setup, and see if that helps. If not, trace every ciruit under the hood starting at the battery until problem is found or ciruits are verified. That one would really suck to do...

    Keep your fingers crossed! Maybe it is all a fluke coming out of the alternator!

    Good luck with it!

    Ratch
    <a target="_blank" href=http://k5.8m.com>k5.8m.com</a>
    **K5 - What more is there to life?**
     
  4. RockBurb

    RockBurb 1/2 ton status

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    Well I know the alternator is bad because it has been making a horrible noise for about a week and a half. also it was tested by a local shop and they also said that it was no good. Im about to go out and start looking at wires again. Alternator was a no go, problem is still there. I do have a trailer harness, but that did not look to be the problem. The batteries are isolated using a Painless 200 amp isolator, and i havent had a problem with it so far.... The only other thing that I can really think of is a while ago at school someone decided that it would be fun to crawl under my truck and cut the wiring harness that goes to the starter. I had to move the solenoid into the engine compartment and solder the wires together, and im pretty sure that one of them is also a fusible link (besides the one that already blew). Anyone think there might be something there?

    84 Burb with 35's and locked front and rear.
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I actually had a fair bit of warning that my alternator was going bad. The internal voltage regulator was fryed I guess. The voltage gauge would fluctuate between 12.5 volts and about 18 volts back and forth, and my headlights would get really bright and then dimmer as the guage would move (so I knew it wasn't the guage...)
    It did this from Kansas to Austin Texas and finally packed it in after I turned and headed for home. All in all I prolly drove about 700 miles from when I noticed i had some wierd problem til it finally quit. Other than the lights getting brighter and dimmer i had no other electrical issues though.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     
  6. newyorkin

    newyorkin 1 ton status

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    Right, you guys got me, I forgot about bearings going on them too. And you're right too, Rene, thinking more, I have seen regulator's go like that, but every alt. I've blown up has just stopped working, and I never noticed until everything started getting darker...
    So if you're running an isolator, the 2nd batts probably not the problem.
    I thought the ground strap thought was a pretty good place to start after reading that. Would it be possible to try and run new wire to the solenoid? Keeping the only connections at point a and point b, with no place to lose signal/short along the way?

    Ratch
    <a target="_blank" href=http://k5.8m.com>k5.8m.com</a>
    **K5 - What more is there to life?**
     
  7. RockBurb

    RockBurb 1/2 ton status

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    Update. I seemed to have fixed the front turn signals by replacing the flasher. The said light work now, and the lights in the dash work (seems slow to me though), but the parking lights do not work as turn signals, they do work as parking lights though. I also noticed that the rear tailights seem to be completely out, no hazard or brake lights, not sure about backup. The wipers I traced to the Pulse Control Module and it looks as though it blew, costs 80 from the dealer so I have to go and check at a yard to see if thats all it is. Any thoughts or ideas would be great! Thanks!

    84 Burb with 35's and locked front and rear.
     
  8. Twiz

    Twiz 1/2 ton status

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    Sounds like you have multipul problems. Most of those sys are not interrelated.

    It needs to be tackled one at a time. Properly diaged and fixed, then move to the next problem.

    Check for a intermitant short to ground (blown fuseable link thing). Fuseable links are the last line of defence to advert a major eletrical fire. That would be the first thing I'd check. A fuseable link is generaly used as a power feed line to the rest of the circuts, it is used to feed power to the fuse panel (fuse panel fuses should blow first, not the link, so don't worry about checking the fuse panel stuff yet) The problem should be between the starter cyl. and the fuse block or power distribution block if so equiped. Look for pinched wireing, rubed threw covering, burnt wireing from over-loads, etc. trace the wires) Sometimes the fuseable links run to the alt. So if the alt took a dive, it might have shorted out the link (not likly from what it sounds like in this case, but possible) Tripple check the dual battery set up.
    Also, Check the ground (as newyorker said) good posibility that could also be a problem. There should be a good solid ground to the body, frame and engine. All three grounds need to be clean and solid. (if you are unsure of the ground, make one- its not hard to do.)

    This list is a bit too long for me, so check that and see what you come up with.


    Twiztid
     
  9. RockBurb

    RockBurb 1/2 ton status

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    Ok, well more interesting revelations. Fixed the tail light markers, for some reason every bulb in the rear end blew out. Replaced them and everything is fine. Havent taken the truck for a drive yet but everything looks ok. Turn signals and everything work. Only thing that I know that does not work right now is the wiper pulse modulator (no different speeds for wipers). I will drive it tomorrow and see if everything looks ok. From what I can tell I must have had one heck of a surge, and im thinking it came off the alternator when it went, well I hope so anyways. Thank you for all the help!

    84 Burb with 35's and locked front and rear.
     

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