Inventors NorthWest: Profile on ProPlug


The purpose of this article is to provide further insight into the functions of Inventors NorthWest and to highlight one of the successful products which has emerged with the support of that organization. Inventors NorthWest is a organization located in Bend, which is focused around support for local area inventors. The group meets monthly with further information available on their website,

ProPlug is an electrical connection system used between a towing vehicle and a trailer. Karl Wagner ( is the inventor of this product. Here is his story.

Wagner always had a fascination for electro-mechanical things. When growing up, nothing in the house was safe from being taken apart to see how it worked. Wagner always gravitated toward electrical systems, often working nights and evenings at home to feed his interest. As he had always been an automobile fan, he soaked up all of the training he could get in electrical systems and put that to work in cars. He obtained work as an electro-mechanical engineer in the automotive industry which put him right where he wanted to be.

As his daughter grew up and got involved in horses, he ended up dealing with the inadequacies of the electrical connectors between horse trailers and the vehicles to tow them. As he was getting frustrated one day with the difficulty of connecting the wires to the trailer plug on the back of his pickup and with a mind that is always looking for a better/easier way to do something, you can guess what his thought was.

Yep, “there has got to be a much easier way to do this.” Upon realizing that the wiring and installation issues with the current trailer connectors are a universal problem and inherent to their design, an idea started forming. Chief among the issues with existing products was that the mounting requirements for a towing vehicle connector have changed very little over time, not keeping up with the applications on new vehicles.

Currently, either drill a big hole in the vehicle for the plug to mount into or hang it from a bracket that has the big hole in it, often placing the plug in a vulnerable location. Both of these options require considerable depth behind the mounting plane for the connector housing to protrude and for the routing of the wiring into the connector housing.

In addition, connecting the wires into the plug requires completely disassembling the connector, which is highly prone to error. In addition, attempting to service a connector that has been in use often becomes a replacement as internal corrosion problems render the connector useless. So, Karl felt it was time to totally rethink how the connector can be mounted, how the wiring connections are made, and how it is tested. In the meantime the auto manufacturers had begun to standardize on the flat blade 7-way connector for vehicles with towing capabilities, which simplified the design process for a new connector system.

The result was Pro Plug, an easy to wire, easy to install, self-testing, surface mount 7-way RV electrical connector that makes it possible to install a connector where you couldn’t before. It works great inside pickup beds for campers and 5th wheels as it can be mounted high on the inside of the bed wall protected under the top bed rail.

Pro Plug also works great as a replacement connector on the mid-90s GM pickups, Suburbans, Yukons and Tahoes with the factory receiver hitch that leaves little room to install a plug, on motor homes and trailers on the rear bumper where the sewer hose is stored, many aftermarket receiver hitches with a flat tube cross bar and the list goes on. Pro Plug has been sold throughout North America.
Though Wagner’s idea of a surface mount style electrical connector was conceived 2003, he didn’t actually start design of the product until late winter of 2006. With the help of electro-mechanical design and CAD (Computer Aided Design) experience, a preliminary design and solid model was ready in about a month. Since the majority of parts of the end product would be injection molded plastic that can take months of time and tens of thousands of dollars to get tooling made just to test the design, a process called FDM (Fusion Deposition Modeling) was used to produce a fully functional set of plastic parts directly from CAD files to build the first prototype in about seven days.

Almost simultaneous with the prototype process was a patent search, which found no other surface mount trailer connector designs, followed by the filing of a provisional patent.

With prototype in hand and an idea of what pricing for production quantities would be, Wagner visited with people in the trailer and RV industry and got enough positive feedback to continue to push forward. The next big step was to commit to build tooling and to actually mold the plastic parts (no small financial investment) and a major decision as to whether to keep the part manufacturing in the U.S. or let it go to Asia.

Fortunately a fellow inventor dropped the name of a great company, R & D Plastics in Hillsboro, Oregon that was able to get tooling made in Asia at a reasonable price and yet competitively make all of the plastic parts in Hillsboro. Along with price, the other motivation for getting tooling made in Asia was at least a month less time. Unfortunately and no fault of R & D Plastics, the tools being container shipped ended up in Mexico for a two week delay.  As soon as the tools were available at R & D, they were put in presses. Wagner drove to Hillsboro to approve first article parts and drove back to Bend two days later with 3,000 sets of parts.

While waiting for tooling and parts, work continued on graphics, packaging, printing, instruction sheets, website, filing for a utility patent, and building a new company for the product, Connect Industries, Ltd.

By fall of 2007, the first production Pro Plugs were being packaged and boxed up for orders that barely trickled in as the U.S. economy was winding down. The RV and trailer industry was taking a major hit from a summer of $4 a gallon gas and rapidly declining home equity, a speed bump that even a large marketing budget could probably not have smoothed out.

With a couple of cases of product in his pickup and duffle bag packed, Wagner set off on a road trip to get some first hand sales experience with his new product. Sales were mediocre at best, perhaps due to lack of sales experience, perhaps due to the time of year, and a problem with the design of the latching system to hold the mating connector into Pro Plug. This became obvious as some of the dealers tried them out. So back to the office to redesign the latch, have the mold modified, order 3,000 new parts, rework all inventory and put some damage control in place on the website.

To help make ProPlug the electrical connector system of choice, design work continued on optional mounting bracket systems and wiring harnesses to create a complete high quality electrical connector system package.

Though ProPlug is available for retail purchase on the website, the major focus for sales is RV and trailer parts distributors and dealers throughout the U.S. and Canada.

The success and applicability of the idea has led Wagner down the path of creating a new version of the ProPlug for commercial tractor/trailer rigs. This is a whole new market for the product.
What did Inventors NorthWest do for Wagner? In the monthly meetings he was exposed to information from a number of experts. These people included patent attorneys, marketing professionals and product designers. He had access to a diverse group of other inventors with whom he could compare notes, discuss problems and look for advice.

Wagner felt so strongly about the value of Inventors NorthWest that he volunteered to serve on the board of directors.   In the end, the idea was Wagner’s born from his interests and experience and his recognition that there was a problem that needed a solution. As his brother says, “give him a battery and some wire and he can make anything work.”

John Herrick, Jr. can be reached at 503-799-3580, jhunterh2001@yahoo.comThis e-mail address is being protected from spambots. You need JavaScript enabled to view it . He is a principal in a local design and product development firm ( The company’s focus is on electro-mechanical design and product development.


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