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  1. Custom Fit Vehicle Wiring
  2. GMC
  3. Sierra
  4. 2003
  5. Demco
FITS 2003 GMC Sierra
Demco 5th Wheel/Gooseneck 90-Degree Wiring Harness with 7-Pole Plug - 10' Long

Demco 5th Wheel/Gooseneck 90-Degree Wiring Harness with 7-Pole Plug - 10' Long

Item # DM8555002
Retail:$262.74
Our Price: $100.51
You Save: $162.23
Custom Fit Vehicle Wiring
Confirmed to Fit
2003 GMC Sierra

with factory 7-Way

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Demco custom fit vehicle wiring for your 2003 GMC Sierra are available from etrailer.com. Installation instructions and reviews for your GMC custom fit vehicle wiring. Expert service, and great custom fit vehicle wiring prices. etrailer.com carries a complete line of Demco products. Order your Demco 5th Wheel/Gooseneck 90-Degree Wiring Harness with 7-Pole Plug - 10' Long part number DM8555002 online at etrailer.com or call 1-800-940-8924 for expert service.
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  • Reviews (64)
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2003 GMC Sierra - Demco 5th Wheel/Gooseneck 90-Degree Wiring Harness with 7-Pole Plug - 10' Long

  • 7 Round - Blade
  • Fifth Wheel and Gooseneck Wiring
  • Demco

Mount this 7-way, RV-style connector in your truck bed to simplify hookup of your 5th-wheel or gooseneck trailer. Harness plugs into existing wiring and retains use of factory 7-pole at the bumper. 90-Degree connector fits into tight spaces.


Features:

  • Provides 7-way, blade-style connector in your truck bed for hassle-free hookup of 5th-wheel or gooseneck trailer
    • Connector can be mounted in truck bed sidewall, tailgate post, or wheel well
    • 10' Long, insulated wiring harness easily reaches from rear bumper to truck bed
  • Plugs into factory wiring - no cutting or splicing
    • Requires that truck have factory tow package
    • Retains use of factory 7-pole connector at rear of truck
  • Offers enhanced weatherproofing with corrosion-resistant terminals and rubber-coated copper wiring
  • Lid with oversize hinge opens 180 degrees for easy connection
  • Constructed of extremely durable ABS plastic
  • Includes self-tapping screws and nylon ties for installation


Specs:

  • Harness length: 10'
  • 5-Year limited warranty


8555002 Demco 5th Wheel/Gooseneck 90-Degree Wiring Harness with 7-Pole Plug - 10'



Customer Satisfaction Score:


Customer Reviews

Demco 5th Wheel/Gooseneck 90-Degree Wiring Harness with 7-Pole Plug - 10' Long - DM8555002

Average Customer Rating:  4.8 out of 5 stars   (64 Customer Reviews)

Mount this 7-way, RV-style connector in your truck bed to simplify hookup of your 5th-wheel or gooseneck trailer. Harness plugs into existing wiring and retains use of factory 7-pole at the bumper. 90-Degree connector fits into tight spaces.

by:

great having extra plugs so my fifth wheel plug is not rubbing my tailgate paint



by:

Perfect fit. Arrived to me quickly.
Thanks
Paula at etrailer!

Rick

5/6/2021

Great product!



by:

Super easy to install. Took me 15 min to get everything routed and hooked up.



by:
2017 GMC Sierra 2500

Nice heavy duty wiring and plug ends. Great instructions and pretty easy install.



by:

Ordered Demco harness for 2011 super duty and for some reason wiring did not match my 5th wheel. Contacted e trailer and was told to ship back and they would send new harness which they did. Installed new harness and works great. Thanks for the help



by:

Have had it installed for a year now works great was easy to install. Would recommend great product.



by:

Ordering was great, delivery was quick, but they dumped all the boxes in the middle of my drive and left, without letting me know. They couldve been stolen. Prices are high compared to others and previous orders I was able to get discounts. The hitch box was completely destroyed, taped and half open in transit. Hopefully no parts are missing. Something has to change. Destroyed boxes equals destroyed products.



by:

still working good.



by: 03/21/2023

The hitch did not come with a cover to cover when not in use. I need a rain cap or cover



by:

Missing a critical part in the box - bed bracket for cable to plug into. Customer Service was great and reordered and ask for warehouse to open box and make sure bracket and cable in new box. Waiting on email and new delivery



by:
2021 Dodge Ram Pickup

great price, very good product, it is a plug in, no extra wiring needed,
put this on my 2021 dodge ram, took about an hour, awesome



by:
2013 Ford F-250 and F-350 Super Duty

Have not yet installed, but a well built part with clear and concise installation instructions. Plug and Play!

Charley S.

10/23/2017

Still happy with all of it.



by:
2022 Dodge Ram Pickup

The Demco 5th Wheel/Gooseneck p/u bed connection is just what I needed. I have always just draped the connection from the trailer over my tailgate and down to the 7pin connector on the bumper, but this is so handy to have and makes it a neater connection. Since my 2022 Ram 2500 came with the hole already provided in the bed wall, it was a breeze to install.



by:
2016 Ford F-250-Super-Duty

Wiring harness was easy to install and is holding up nicely a year and half later. Great product and price too from etrailer.



by:
Ram 3500

Easy quick install and plenty of cable to run this to any location within the bed of your truck. i installed this in my New 2020 GMC 3500 Denali in less than 30 minutes!! Perfect fit as always from etrailer!!



by:
2016 GMC Sierra 2500

directions are miss leading . 2" hole isn't big enough as another tab has been added which makes swinging the plug thru the hole impossible . I have a dremel tool at home and ground a tab area for the tab to go thru and was easy as pie then . Plug hook up easy and all was good after getting it thru the hole.



by:

Not to difficult to install. It will require 2 people to get the bolts torqued down. Handles a 14000 lb fifth wheel with ease



by:
2006 Chevrolet Silverado

While I had to wait for the product because of it was back ordered, the wait was not unreasonable and the etrailer staff keep me updated the whole time. The harness is high quality. Service was top notch.



by:
2019 Ram 2500

The video was fantastic as well as questions being answered in regards to my specific truck. Thanks again..



by:

Love it. Rides great. Pulled over 20 models with it.



by:

Easy install. Connected to factory harness and was in in about 1/2 hour.



by:

Bonjour, très bon produit, connexion fait pour mon camion et facile à installer.



by:

makes for a clean installation



by:

both products were shipped well packed and undamaged very impressed with the customer service and the shipping thanks again

Gregory

4/4/2019

good quality very satisfied thanks



by:

Easy install!!!!


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Info for this part was:

Employee Andrew K
Video by:
Andrew K
Employee Kathleen M
Video by:
Kathleen M
Employee Jonathan Y
Video by:
Jonathan Y
Employee Lindsey S
Edited by:
Lindsey S
Employee Jameson C
Expert Research:
Jameson C
Employee Joshua S
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Joshua S
Employee Jacob T
Video Edited:
Jacob T
Employee Dustin K
Video Edited:
Dustin K
Employee Chris R
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Chris R
Employee Zach D
Video Edited:
Zach D
Employee Cole B
Installed by:
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Employee Amanda M
Written by:
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Employee Shane H
Test Fit:
Shane H
Employee Robert C
Test Fit:
Robert C
Employee Ryan G
Test Fit:
Ryan G
Employee Clayton O
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Clayton O
Employee Bradley B
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Employee Hannah L
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