2004 Tahoe keeps blowing left turn fuse

Discussion in 'Chevy Tahoe Forum (GMC Yukon, Cadillac Escalade)' started by coppcarz, Nov 14, 2010.

  1. coppcarz

    coppcarz New Member

    Ok, last month, this started, i put on the left turn signal, hear one click, and then nothing...............................and every time I do this, it burns the left turn fuse......but even after blowing the fuse, if i engage the left turn, it still makes a click.

    So I changed the flasher....and tried it, it blew the fuse.....

    I left in the new flasher, removed the rear left turn bulb, and tried it, and the fuse blew......

    I left in the new flasher, removed the front turn bulb and tried it, and the fuse blew......

    I left both bulbs out with the new flasher, and the fuse blew

    the sockets look clean....no burns...bulbs looked good, plus they were pulled out and the problem still continues..........flasher seems good to....

    what's next? the switch?
  2. stephan

    stephan Rockstar 4 Years 5000 Posts

    Welcome to the GM truck club Copp. It could be the ts switch, but there are easier things to check before that. BTW I like your diagnosis procedure so far. It was right down the line & thorough. Most don't do it so well. I would look under the back where all your trailer wireing is. If you haven't used it before it should be tucked away up there, probably above the spare tire. Look for water in the plug, or chaffing of the wires where they could be shorting against metal. Also look at the wireing for the LR turn sig while you're under there. It sounds like a direct short to ground since it is every time, rather than an intermittant prob, so it should be easy to find. Start at the socket & work your way foreward untill you can't follow it any more. If no luck there go to the LF & do the same, starting at the socket. This one should be easy to find since it's so definite & not intermittant.
  3. coppcarz

    coppcarz New Member

    Thanks for taking the time to reply Stephan,

    OK, I'll check the wiring....but I just towed a trailer this weekend and I know that the left and right trailer circuits have their own fuse (also 10 amp, as the turn signal fuse)................so wouldn't that fuse blow first????

    If the short is in the left trailer light wiring and I were to pull that fuse out, that should prevent the fuse from blowing on the regular left turn circuit.......correct?
  4. stephan

    stephan Rockstar 4 Years 5000 Posts

    I'm not sure if pulling the one fuse would keep the other from blowing, but I don't think it would. Only thing I know is that they are interconnected (probably at the relay, hazard & t s switch) because left truck & trailer light both blink at the same time. I would still do close checks of wireing looking for short as explained above before spending any money on parts or faulting t s switch. You don't want to pull t s switch unless as a last resort.
    When you pulled your trailer this weekend were all the left turn signal lights working properly on both truck & trailer??
  5. coppcarz

    coppcarz New Member

    No, the left would't work at all on both the trailer and the truck....if they are seperate lines, then would make sense that it is the t/s switch???
  6. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

    They could be separate lines but I agree with Stephan that they are interconnected and most likely cause is left side wiring is grounding/shorting out someplace. I think the reason the trailer has its own fuse is so that if something happend to the trailer electrical system, then it would blow that fuse first, thus limiting the surge impact to the trailer wiring only and keep your regular signal system working. So pulling out the trailer fuse I do not think would work either.

    If you do replace the turn signal switch, try to buy from a retailer that will return it if it doesn't solve your problem. It sounds like this could be a pricey item and most places will not return installed electrical items. I would just hate to see you spend money on something you don't need.
  7. coppcarz

    coppcarz New Member

    Ok guys, well I was thinking that if the fuse to the trailer wiring is pulled, then it would kill any connection between the trucks turn signal wiring lines and any bad possible bad wiring located in the back tow receiver wiring......problem is this truck was very well kept, never towed, so everything looks fine.....

    If I can get a new switch....can I just plug it into the harness and test it, or must it be fully installed onto the column??? What exactly is needed to remove and replace the signal switch?????

    If there is a short anywhere in the wiring, would there be continuity between the two prongs in any of the sockets????
  8. stephan

    stephan Rockstar 4 Years 5000 Posts

    OK, if you don't want to check your wiring, then go buy yourself an ohm meter.
    Pull out your l.f. & l.r. t.s. bulbs.
    Make sure key is OFF, t.s. switch is in neutral position & hazard switch is OFF.
    Ground one probe of your ohm meter & put the other lead on the turn signal contact in the socket.
    If the ohm meter shows continuity the wire is shorted to ground, & you are going to have to follow your wiring to find it.
    If no continuity on the rear, then go do the same check on the l.f. turn signal.

    If you don't want to buy an ohm meter, or don't know how to use one, then go back to my first post & do what I told you to do in the last half of that post.

    As far as buying a new turn signal switch, there's a 95% chance it will also blow your fuses. When t.s. switches go bad, they don't make contact anymore, & don't transfer power to your lights. This one IS providing power & is causing the fuse to blow, because it is sending voltage down your wiring to the point where it is shorted to ground.
    Last edited: Nov 30, 2010
  9. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

    Stephan...Are you sure about the 95% chance of it blowing the fuse again?? It seems to me this number is off by a point or two. Can you work on your percentages please?

    coppcarz - I'm not sure if it is as simple as plugging the turn signal switch in or if you have to actually install it....someone else will have to chime in on that. In the meantime, the link below takes you to a thread that will connect you with a Chiltons if you want to see how much work is involved.

    Good luck and let us know how it goes!!

    Last edited: Nov 30, 2010
  10. stephan

    stephan Rockstar 4 Years 5000 Posts

    Lol Mike... I would have raised the percentage but I wanted to leave a 5% margin for error in case someone had dropped a paper clip or some other little piece of metal down into the turn signal switch that could be causing the short. You always have to leave some margin of error for that rat bastard "Murphy" & his law.

Share This Page

Newest Gallery Photos