1978 GMC C25 Trailer Wiring

Keep Your 1978 GMC C25 in Top Shape with Quality Trailer Wiring

Whether you’re repairing or upgrading your Trailer Wiring, using high-quality parts is key to keeping your 1978 GMC C25 looking sharp and performing at its best. At Advance Auto Parts we carry a wide selection of dependable options, including Trailer Wiring Kits and Trailer Wiring Harness. Whether you’re replacing a damaged part or enhancing your truck’s style and protection, you’ll find exactly what you need to get the job done right.

Competitive Prices and Extensive Inventory

The average price for a 1978 GMC C25 Trailer Wiring at Advance Auto Parts is around $21.16, with a range that starts at $7.99 and goes up to $27.99. With 3 options in stock from 2 trusted brands, finding the right fit is easy. Popular picks like Vehicle Wiring Kit and Custom Wiring Harness (4-Way Flat Output) start at just $27.49 and offer a great balance of form and function.

Explore Related Parts

While you’re upgrading or replacing your Trailer Wiring, don’t forget to check out other key components like Trailer Hitches and Winches. At Advance Auto Parts, we’re here to help you keep your 1978 GMC C25 in peak condition, inside and out.

Essential 1978 GMC C25 Trailer Wiring

Hopkins – Vehicle Wiring Kit (Part No.41105)

Vehicle Wiring Kit

from

$27.49
Dont splice onto your vehicles factory wiring harness. Simply plug in this Hopkins® vehicle wiring kit featuring exact OEM matching connectors for a perfect weather-tight fit. This kit includes the accessories needed to get you towing faster.

Product Features:
  • Plug-In Simple® Wiring Kit
  • Utilizes OEM Connectors For Enhanced Fit And Weatherproofing
  • Includes Vehicle Side 4 Flat
  • Corrosion Resistant Terminals
  • Impact And Corrosion Resistant
  • Includes Dust Cover And Grease Packet To Prevent Corrosion
  • Includes Step-By-Step Instructions
See More

CURT – Custom Wiring Harness (4-Way Flat Output) (Part No.55311)

Custom Wiring Harness (4-Way Flat Output)

from

$27.99
If your vehicle is not equipped with wiring for towing a trailer, CURT custom wiring is the ideal solution. A custom wiring harness — also called a T-connector — is a simple, plug-and-play electrical device that plugs into your automotive electric system and provides a standard, universal trailer wiring connection. This is done using two or more vehicle-specific, OEM-compatible connectors to plug into the taillight assembly, eliminating the need for cutting, splicing and soldering during installation. Custom wiring harnesses are made vehicle-specific, and while they are not available for all vehicles, they do offer one of the fastest, easiest and most secure ways to wire a vehicle for towing. This particular plug-in harness provides a 4-way flat connector socket and is designed to be a custom wiring harness to fit certain years of the Chevy Blazer, K5 Blazer, C10, C20, C30, K10, K20 and K30 pickup or Suburban and GMC C15, C1500, C25, C2500, C35, C3500, K15, K1500, K25, K2500, K35 and K3500 pickup or Suburban (to verify your vehicle compatibility, see application info). It comes with all necessary wiring components to establish a reliable trailer wiring connection, as well as a dust cover to keep the connector clean when not in use. You have a picture in mind of your next destination — maybe it’s the boat landing at your favorite fishing spot, maybe it’s a campsite that overlooks one of nature’s masterpieces, or maybe it’s the next big jobsite. However, turning that picture into a reality takes more than just daydreaming. It takes a solid connection and the right amount of power. CURT custom wiring is made with some of the most sophisticated technology in the industry and is designed to install with ease, giving you a long-lasting electrical connection for your towing hitch setup.

Product Features:
  • Plugs into existing OEM vehicle socket to provide a 4-way flat socket
  • Simple plug-and-play design eliminates the need for cutting or splicing
  • 4-way flat output connects tail lights, brake lights and turn signals
  • Dust cover included to keep connector clean when not in use
See More

Hopkins – 48035, 4 Flat Vehicle Side Towing Connector (48") (Part No.48035)

48035, 4 Flat Vehicle Side Towing Connector (48")

from

$7.99
Get your vehicle ready to tow the most common type of trailer on the road by installing this vehicle side 4 flat. This 4 flat connector carries the trailer’s basic lighting and includes printed wire functions that make installation quick.

Product Features:
  • 48 inch length
  • Corrosion Resistant Terminals
  • Most Commonly Used Trailer Connector
  • Found On Small Boat/Utility
  • Printed wire functions for easy wire reference
  • Printed Wire Functions For Easy Wire Reference
  • 100 Percent Tested
See More

Most Popular Trailer Wiring Kits for 1978 GMC C25s

Enhance your 1978 GMC C25 with one of the 2 Trailer Wiring Kits we have in stock, starting at just $7.99.

Hopkins – 48035, 4 Flat Vehicle Side Towing Connector (48") (Part No.48035)

48035, 4 Flat Vehicle Side Towing Connector (48")

from

$7.99
Get your vehicle ready to tow the most common type of trailer on the road by installing this vehicle side 4 flat. This 4 flat connector carries the trailer’s basic lighting and includes printed wire functions that make installation quick.

Product Features:
  • 48 inch length
  • Corrosion Resistant Terminals
  • Most Commonly Used Trailer Connector
  • Found On Small Boat/Utility
  • Printed wire functions for easy wire reference
  • Printed Wire Functions For Easy Wire Reference
  • 100 Percent Tested
See More

CURT – Custom Wiring Harness (4-Way Flat Output) (Part No.55311)

Custom Wiring Harness (4-Way Flat Output)

from

$27.99
If your vehicle is not equipped with wiring for towing a trailer, CURT custom wiring is the ideal solution. A custom wiring harness — also called a T-connector — is a simple, plug-and-play electrical device that plugs into your automotive electric system and provides a standard, universal trailer wiring connection. This is done using two or more vehicle-specific, OEM-compatible connectors to plug into the taillight assembly, eliminating the need for cutting, splicing and soldering during installation. Custom wiring harnesses are made vehicle-specific, and while they are not available for all vehicles, they do offer one of the fastest, easiest and most secure ways to wire a vehicle for towing. This particular plug-in harness provides a 4-way flat connector socket and is designed to be a custom wiring harness to fit certain years of the Chevy Blazer, K5 Blazer, C10, C20, C30, K10, K20 and K30 pickup or Suburban and GMC C15, C1500, C25, C2500, C35, C3500, K15, K1500, K25, K2500, K35 and K3500 pickup or Suburban (to verify your vehicle compatibility, see application info). It comes with all necessary wiring components to establish a reliable trailer wiring connection, as well as a dust cover to keep the connector clean when not in use. You have a picture in mind of your next destination — maybe it’s the boat landing at your favorite fishing spot, maybe it’s a campsite that overlooks one of nature’s masterpieces, or maybe it’s the next big jobsite. However, turning that picture into a reality takes more than just daydreaming. It takes a solid connection and the right amount of power. CURT custom wiring is made with some of the most sophisticated technology in the industry and is designed to install with ease, giving you a long-lasting electrical connection for your towing hitch setup.

Product Features:
  • Plugs into existing OEM vehicle socket to provide a 4-way flat socket
  • Simple plug-and-play design eliminates the need for cutting or splicing
  • 4-way flat output connects tail lights, brake lights and turn signals
  • Dust cover included to keep connector clean when not in use
See More

Best-Selling 1978 GMC C25 Trailer Wiring Harnes

Upgrade your C25 with our best-selling Trailer Wiring Harnes.

Hopkins – Vehicle Wiring Kit (Part No.41105)

Vehicle Wiring Kit

from

$27.49
Dont splice onto your vehicles factory wiring harness. Simply plug in this Hopkins® vehicle wiring kit featuring exact OEM matching connectors for a perfect weather-tight fit. This kit includes the accessories needed to get you towing faster.

Product Features:
  • Plug-In Simple® Wiring Kit
  • Utilizes OEM Connectors For Enhanced Fit And Weatherproofing
  • Includes Vehicle Side 4 Flat
  • Corrosion Resistant Terminals
  • Impact And Corrosion Resistant
  • Includes Dust Cover And Grease Packet To Prevent Corrosion
  • Includes Step-By-Step Instructions
See More

FAQs for 1978 GMC C25 Trailer Wirings

What are the best-selling Trailer Wirings for 1978 GMC C25s?

Out of 3 Trailer Wirings that fit 1978 GMC C25s, the following parts are the top sellers:

What’s the price range for 1978 GMC C25 Trailer Wiring?

The prices of Trailer Wiring for the 1978 GMC C25 range from $7.99 up to $27.99 for the most premium parts.

What is the average price of a Trailer Wiring for a 1978 GMC C25?

The average price for Trailer Wirings for the 1978 GMC C25 is $21.16. Keep in mind the variety of part types within our Trailer Wiring category, where you are likely to find a wide range of prices across a variety of parts and components.

Does Advance Auto Parts sell Trailer Wiring for other GMC C25 model years?

Yes, we carry Trailer Wiring for 2 model years of GMC C25s between 1975 and 1977. The following model years are the most popular for Trailer Wiring purchases: 1977, 1976, and 1975.

What are the cheapest Trailer Wiring for my 1978 GMC C25?

The cheapest 1978 GMC C25 Trailer Wiring we carry are:

Does Advance Auto Parts sell Trailer Wiring for any other 1978 GMC models?

Yes. We stock Trailer Wiring for 9 other popular 1978 GMC models. Some of the most popular are 1978 Jimmy Trailer Wiring, 1978 Caballero Trailer Wiring, 1978 K25 Trailer Wiring, 1978 K15 Trailer Wiring, and 1978 G25 Trailer Wiring.

What are the top-rated Trailer Wiring that fit the 1978 GMC C25?

The one 1978 GMC C25 Trailer Wiring we have in stock is the 48035, 4 Flat Vehicle Side Towing Connector (48"). It is rated 3.5 stars and costs $7.99.

What types of Trailer Wiring do you sell for my 1978 GMC C25?

As of 11/2/25, these are some of the most in-demand types of Trailer Wiring for a 1978 GMC C25:

Can I get help with 1978 GMC C25 Trailer Wiring orders?

Contact our customer support team by chat or phone, through the help desk page, where you can find instant answers about GMC Trailer Wiring and more.

What is your return policy for GMC C25 Trailer Wiring?

Advance Auto Parts keeps returns simple. For new GMC C25 Trailer Wiring and accessories, your online orders can be returned, in their original condition, within 45 days. For requirements, see the returns page.