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Electrical Gremlins

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by aksidentproan, Feb 18, 2002.

  1. aksidentproan

    aksidentproan 1/2 ton status

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    Im pissed!!! I took my dash apart to try to install a tachometer. The tach was to big so i put everything back together and now none of my rear lights work (brake lights, signal lights, running lights) The only thing i disconnected was the big master plug that plugs into the back of the dash and the speedo cable. Where are the grounds on theses trucks. Anythig else i should know? Any help is appriciated.

    Evan

    1970 Blazer, <font color=orange>ORANGE</font color=orange>, 3-speed manual, 33's <a target="_blank" href=http://community.webshots.com/user/aksidentproan>Love Shack Pictures</a>
     
  2. Blazer1970

    Blazer1970 1/2 ton status

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    I would guess that a wire or wires came loose from the light switch while you were screwing around with the IP.

    Tim

    70 Blazer CST 4X4 350 SM465 NP205
    87 Burb 4X4 350
    01 GMC 2500HD 4X4 Duramax/Allison
     
  3. aksidentproan

    aksidentproan 1/2 ton status

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    when you say light switch, do you mean the switch that turns on the head/parking lights or is there another relay/switch? Thanks

    Evan

    1970 Blazer, <font color=orange>ORANGE</font color=orange>, 3-speed manual, 33's <a target="_blank" href=http://community.webshots.com/user/aksidentproan>Love Shack Pictures</a>
     
  4. Klef72K5

    Klef72K5 1/2 ton status

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    Is it just the rear of the Blazer? The front all works? If so it sounds like you some how disconnected your rear intermediate wiring harness. This may sound stupid but did you check your fuses? Including the two fuses under the hood?

    <a target="_blank" href=http://wsphotofews.excite.com/031/rw/Jo/og/t488200.jpg>http://wsphotofews.excite.com/031/rw/Jo/og/t488200.jpg</a>
     
  5. aksidentproan

    aksidentproan 1/2 ton status

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    i checked the fuse panel inside my truck but where are the fuses under the hood and where would the intermediate harness be? Thanks for the help.

    Evan

    1970 Blazer, <font color=orange>ORANGE</font color=orange>, 3-speed manual, 33's <a target="_blank" href=http://community.webshots.com/user/aksidentproan>Love Shack Pictures</a>
     
  6. Klef72K5

    Klef72K5 1/2 ton status

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    You never answered my question if the front lights were out also. This would help me and other on helping you!
    On the wire harness the plug is near the distributor. One end goes into the fire wall and the other end goes underneath the Blazer to the rear. There it is connected again to tail lights and rear side markers harness.
    For the fuses they both have black wires and are in a rubber boot to keep moister out. One of them should be connected to your junction post over by your battery it is mounted on the fender. The second one is over near the drivers side headlight. That black wire will have a white stripe on it. They both are small fuses and I blew them when I was playing around with my dash also. This is most likely your culprit!

    <a target="_blank" href=http://wsphotofews.excite.com/031/rw/Jo/og/t488200.jpg>http://wsphotofews.excite.com/031/rw/Jo/og/t488200.jpg</a>
     
  7. aksidentproan

    aksidentproan 1/2 ton status

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    i think i said it was just my rear lights in my first post but in case i didnt, its just my rear lights. Thanks for the info, ill go check it out now, i havent been able to drive my truck for a few weeks[​IMG]

    Evan

    1970 Blazer, <font color=orange>ORANGE</font color=orange>, 3-speed manual, 33's <a target="_blank" href=http://community.webshots.com/user/aksidentproan>Love Shack Pictures</a>
     
  8. aksidentproan

    aksidentproan 1/2 ton status

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    OK, i checked both those fuses and the one by the battery hasnt been connected for about 2 months ever sinse my truck caught on fire. I think i broke the one one by the headlight when i opened it, how do i replace these fuses or do i have to replace the whole boot and what amp should the fuse be? Thanks alot

    Evan

    1970 Blazer, <font color=orange>ORANGE</font color=orange>, 3-speed manual, 33's <a target="_blank" href=http://community.webshots.com/user/aksidentproan>Love Shack Pictures</a>
     
  9. Klef72K5

    Klef72K5 1/2 ton status

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    You can replace just the fuses. They can be a pain in the ass to get out! They are suppose to 4 amp fuses. Walmart didnt carry any fuses that small. I ended up at Auto Zone. Did you have rear lights after your truck caught fire?

    <a target="_blank" href=http://wsphotofews.excite.com/031/rw/Jo/og/t488200.jpg>http://wsphotofews.excite.com/031/rw/Jo/og/t488200.jpg</a>
     
  10. aksidentproan

    aksidentproan 1/2 ton status

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    my rear lights still worked after my truck caught on fire. Im just goin to replace the whole fuse holder with ones that are easier to replace.

    Evan

    1970 Blazer, <font color=orange>ORANGE</font color=orange>, 3-speed manual, 33's <a target="_blank" href=http://community.webshots.com/user/aksidentproan>Love Shack Pictures</a>
     
  11. Klef72K5

    Klef72K5 1/2 ton status

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    Best of luck! If I can help in anyway email me

    <a target="_blank" href=http://wsphotofews.excite.com/031/rw/Jo/og/t488200.jpg>http://wsphotofews.excite.com/031/rw/Jo/og/t488200.jpg</a>
     
  12. aksidentproan

    aksidentproan 1/2 ton status

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    it still doesnt work. I replaced those fuses with new holders and bladed fuses. my brake lights and signal lights still dont work but my running lights do. and another thing. When i turn my parking lights on my left turn signal indicator on my dash comes on but when i look at the light...its not on. but when i turn my parking lights off my left siganl works again. And when i jigle the headlight switch w/ the lights on the left siganl indicator flickers so i dont know what the hell is goin on but its not making me very happy. Where are the ground points on first gen K5's? i could have ripped off a ground when i was messin w/ stuff. Thanks

    Evan

    1970 Blazer, <font color=orange>ORANGE</font color=orange>, 3-speed manual, 33's <a target="_blank" href=http://community.webshots.com/user/aksidentproan>Love Shack Pictures</a>
     
  13. Klef72K5

    Klef72K5 1/2 ton status

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    Do you have back-up lights? Do you have parking lights now on the tail lights? Is your sidemarkers working in the back? This also will sound stupid but did you check the tail light bulbs? When you were playing with the dash instead of blowing the fuse you blew your light bulbs.
    Maybe there is a short in your light switch.

    http://community.webshots.com/user/klef72k5
     
  14. aksidentproan

    aksidentproan 1/2 ton status

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    When my truck was converted from 3-on-the-tree to 3 on the floor they put a switch on the dash that manually activates the back up lights and those still work. My side markers do work but only as running lights(just like the tail lights). If my rear running lights work how could the bulbs be burnt or are there 2 different fillements(one for running, one for brake and signal)? Thanks

    Evan

    1970 Blazer, <font color=orange>ORANGE</font color=orange>, 3-speed manual, 33's <a target="_blank" href=http://community.webshots.com/user/aksidentproan>Love Shack Pictures</a>
     
  15. 70jimmy

    70jimmy 3/4 ton status Premium Member GMOTM Winner

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    There are two filaments in the rear taillight bulbs. One for running lights and one for signal/brake lights. They should be GE1157 bulbs. A problem I had was when I checked the bulbs I found a bunch of greasy putty type stuff in the bulb socket between the bulb and contacts. I cleaned that out and lights worked much better. Another shot in the dark: do your 4 way flashers work? If so try switching your flasher units around. Swap the 4way unit with the signal. This is located on your fuse block. The round metal looking things if youre not familiar with them.

    I hate electrical problems!!!!!!!!!
     
  16. ntaj*ep

    ntaj*ep 1/2 ton status

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    just a suggestion, first relax, OK, now take your test light and make sure you have a good ground, and it works. Now recheck all the fuses under the dash, take your lead and with the key on touch your lead to the ends of the fuses in the panel, if the light works on one side but not the other you have a bad fuse or connection. If the fuses are OK, recheck your connection at the headlight switch make sure the switch is tight and the connectors are fully plugged in even unplug them and re secure, also any other connectors that may have been disturbed, coulmn, inst. cluster,brake switch, anything,. If it still is a problem, post your findings, and remember with electrical problems relax.

    The Red Beast<P ID="edit"><FONT class="small">Edited by ntaj*ep on 02/24/02 12:34 PM.</FONT></P>
     
  17. aksidentproan

    aksidentproan 1/2 ton status

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    I looked at my bulbs and sure enough.....1 of the fillements in each bulb were gone so i went to pep boys and got new ones but i havent tried them yet beacuse my truck is up on jack stands getting lifted a few inches and that should be done by next weekend. I am the stupidest man alive!!!!!!!!! stupid bulbs. Anyway...thanks for all the help everyone...this board is a life-saver for a youngin like me.

    Evan

    1970 Blazer, <font color=orange>ORANGE</font color=orange>, 3-speed manual, 33's <a target="_blank" href=http://community.webshots.com/user/aksidentproan>Love Shack Pictures</a>
     

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