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lfr101's avatar
lfr101
Explorer
Oct 29, 2013

Trailer wiring caused fire under dash

A friend of mine picked up a 18 ft House trailer to tow with his Ford Ranger.He knows it is small but is talking his wife into a bigger truck.

He towed the truck home with a GMC truck.

He took the truck to a major truck/trailer rental company that has a U in their name to have the 7 pin plug and brake controller installed.
When he got home he backed up to the trailer to try it out, once plugged he went to check out the light ,going back to the truck there was smoke coming from under the dash.Unplugging the truck saved it from burning up.

He went back to the installer and they question him saying that maybe the trailer was wired for a GMC not a Ford .I hooked the trailer to my Dodge and they all worked OK.

Now I was under the believe that all trailers are wired the same so they can be pulled by any type of truck.
The ford dealer said it would be $1300.00 to repair it.
It has been over 3 weeks and they (company U) are still jerking him around about paying for the damage.

My question is are are trailer wired the same ?

They want to send a insurance person to look at the trailer,
Thanks D

13 Replies

  • ol_Bombero-JC's avatar
    ol_Bombero-JC
    Explorer
    Oct 31, 2013
    dougrainer wrote:
    1. IF the fire and smoke was under the dash, only thing causing that would be a miswire of the Brake controller.
    2. If so, then the installer was an idiot. You ALWAYS make sure the circuits are fused. BOTH the brake activation wire and the BLUE trailer brake wire AT the front of the truck close to the brake controller. If fused, you will not have such a problem.
    3. Professional installers have a Tow Brake Doctor tester. After you do the work, you just plug it into the 7 way and it will tell you if all 7 circuits are correct and functioning.
    4. As another poster stated, IF the parts changer said the different model/brand trucks are wired differently, he IS an idiot. Doug


    3a. Cheap *Amateur Installers* use a test light - either home made or store bought. Then check each pin individually..:W

    BTW - many years ago, while renting a utility trailer, the employee "fished" out the wires for tails/turn/stop, started poking safety pins (through the wires) for connections.
    He must have been out of the "clamp-on" piercing type - which aren't much of an improvement. Called a halt to that in short order!.:(

    Lesson learned.
    Always carry a "made-up" 7-pin and 4-pin connector with a few inches of wire for each pin in my tool box. Test light also.

    BTW - It's not rocket science. U-Haul employee screwed up..:S

    .
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Oct 29, 2013
    Well you can come to me and I sure as hell don't rent trailers if you catch my drift...
  • dougrainer's avatar
    dougrainer
    Nomad
    Oct 29, 2013
    1. IF the fire and smoke was under the dash, only thing causing that would be a miswire of the Brake controller.
    2. If so, then the installer was an idiot. You ALWAYS make sure the circuits are fused. BOTH the brake activation wire and the BLUE trailer brake wire AT the front of the truck close to the brake controller. If fused, you will not have such a problem.
    3. Professional installers have a Tow Brake Doctor tester. After you do the work, you just plug it into the 7 way and it will tell you if all 7 circuits are correct and functioning.
    4. As another poster stated, IF the parts changer said the different model/brand trucks are wired differently, he IS an idiot. Doug
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Oct 29, 2013
    There is one, and only one, standard way to wire a trailer. You can google "7-pin trailer connector" and find many sites that all agree on how it should be wired.

    The one thing that is different is brake controllers..

    The wires, in no particular order, are Ground, Left Turn, Right Turn, Tail Lights, Brakes, Battery and Aux (often not connected but may be used for back up lights or some such)

    It matters not if the tow vehicle is Ford, GM or Chrysler corp or something else entierly the plugs are identical.

    Now.. There are some exceptions.. But those will be cars that are towed, not trailers.

    Example.. My towed uses a six pin.. Some trailers have a six pin two (Delete AUX from the list above) but the two are different. The six pin on the motor home that towes the car was installed at the same time the car was modified by the same installer, so they match.

    Ground, Tail, RT/Stop LT/STOP, Pump power and alarm sense are the six pins.

    (Remco Towing LP-1 Lube pump on car to protect ye old tranny)
  • campinginthewoo's avatar
    campinginthewoo
    Explorer
    Oct 29, 2013
    Well here's one for ya I have a 2003 Ford Explorer and a 204 F250 CC and when I hooked up my 7 pin TT to my F250 CC everything works just fine but when I hooked up my explorer it blew the fuse to the electronic mirror and back up lamps. My previous truck was a 1996 Chevy Silverado and no problems there either I wonder what's different? I have only pulled my TT once with the explorer (it's ultra lite) and had brakes lights etc....but I lost the fuse in the explorer and it's the only trailer I've ever pulled with it. And only did it because my truck tranny decided to break when I got to campground thank god I was close enough to go home and get the explorer....
  • Gene_Ginny's avatar
    Gene_Ginny
    Explorer
    Oct 29, 2013
    lfr101 wrote:
    ... He went back to the installer and they question him saying that maybe the trailer was wired for a GMC not a Ford ....
    That installer's statement clearly shows he/she has no idea what he/she is doing and should never be allow to wire anything.
  • KD4UPL's avatar
    KD4UPL
    Explorer II
    Oct 29, 2013
    The installer is full of BS. The wiring pin out is the same. It's not the trailer's fault.
  • powderman426's avatar
    powderman426
    Explorer
    Oct 29, 2013
    camperpaul wrote:
    The #18 or #20 wiring in a lot of vehicles is really too small to handle the current used by the parking and tail lights ...

    When you add the clearance and tail lights on the trailer, it's a fire waiting to happen.

    Standard vehicle lighting: 4 X 36 Watt lamps = 12 Amps.

    Trailer lighting = ~8 to ~12 Amps.

    Total = ~20 to ~24 Amps.



    Isn't that the reason they make fuses??

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