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So I have a dent in my hood.... from the inside

Discussion in 'GM Electrical Tech' started by Big_Ben, Sep 27, 2011.

  1. Big_Ben

    Big_Ben New Member

    Long story short, about a week ago I noticed a tiny dent in my hood popping up from the inside. I pop the hood, look inside and am surprised to find a giant hole in the plastic shield on top of the fan! No serious damage noted to the fan blades or anything else, guess I got lucky. I'm assuming it was a rock I may have picked up when I went through a deep puddle on a muddy road.

    Anyway, coincidentally a few days later I offered to help a friend pick up his boat from a marina. Turns out my trailer lights, which all worked beautifully in the past suddenly don't work at all. Not one. I know it's my truck and not the trailer. I've checked all fuses (one was blown, but when I replaced it, no change) and now I'm needing to trouble shoot the problem further.

    If no lights work at all, to me that means the whole harness is shot. I'm wondering if it has something to do with the dent in my hood? Maybe that deep puddle shorted out something? Or maybe the rock also cut through the entire harness somewhere? The latter is highly unlikely, I realize, but you never know.

    Any tips for the best way to go about trouble-shooting this problem? My overall mechanical knowledge would be intermediate-advanced but when it comes to electrical it's more towards the basic level.
  2. dgallions

    dgallions New Member

    It is way more likely that it would be the trailer and not the truck. I would double check the trailer wiring first as it will be the easiest to get to. It doesn't take much to knock out lights on a trailer, corrosion around a ground can be a nightmare to find and make all the difference. Have you checked the fuse to make sure it didn't blow again when you hooked back up to the trailer? If the fuse is still good, check at the connector for voltage. It is easiest to just check each pin to ground (truck frame works best for ground). If you are getting 12 volts there, your problem is on the trailer. I would think that if the rock hit your harness in the front of the truck you would have more problems than just trailer lights. Also, if something shorted out from the water, your fuse should have protected everything and replacing the fuse would fix the problem in most cases.
  3. sstoner911

    sstoner911 New Member 1000 Posts

    AS mentioned before I would see if you have 12v at the harness and go from there.
  4. Big_Ben

    Big_Ben New Member

    There is no power at the tailgate end of the harness. I have one of those light testers, and no matter which lights I try, nothing works from my truck. The fuse that was blown was just a trailer parking brake light or something. The fuses for signal/brakes etc were all fine.

    I guess I'm going to have to crawl underneath and see if I can find anything out of the ordinary. I hate dealing with trailer wiring. Thanks for the starting points though!
  5. sstoner911

    sstoner911 New Member 1000 Posts

    Ya I would start probing the wires and see if you stop getting 12v at some point...maybe its the trailer plug on the truck? I hate electrical issues...they are always a test of my patience!
  6. dpeter

    dpeter Member

    It is most likely a lost ground if nothing works and it could be truck or trailer. If you access to another trailer then try that or try the boat trailer on a different vehcle. I have lost grounds in all manner of ways from cut wires, corrosion, wires pulled out of connectors to name a few. If you have some jumper cables, use them to connect vehicle frame to trailer frame to do a quick check for a ground issue.
  7. Big_Ben

    Big_Ben New Member

    Yea, I'm hoping it's just a lost ground from corrosion and that the ground wire is easy to find. The trailer plug on my truck is 7-way, and I use an adapter for 4-way flat. (Yes I've tested the adapter on a another vehicle, and yes the trailer lights work fine as I tested them on another vehicle as well. It's definitely my truck.)

    I'll get underneath and start digging around for a ground wire, I'm assuming it would be right near the front end?

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