How to Test the Trailer Light Functions of a Trailer with a 4-Way
Question:
Hello,my trailer has 4 prong3 male/1female connector at trailer tongue. Is there a dependable basic tester that will not only check for electricity at vehicle connector,but I can plug the trailer directly into to insure my trailer lights function WITHOUT a vehicle being attached. I dont have the rental truck here yet and want to insure lights on trailer work,before I pick up truck. thank you for your answer! The truck is a rental, The Pace is 2003 model CS612SA 6x12 single axle
asked by: Ran M
Expert Reply:
There is, but I will warn you it's pretty expensive. The Hopkins Tow Doctor Trailer End Test Unit # HM50928 is designed to test the connector on a trailer for function and would be perfect for what you are trying to do. Check out the review video I attached.
A much more inexpensive option would be to use a jumper wire from a car battery's positive post to put voltage on all of the pins of your trailer's connector.
You would need to test the three male pins next to the female pin. The one closest to the female pin will be the running lights. This should light up all of the lights on the trailer when voltage is applied. The taillights will be dimmer but still lit. The pin next to this one will be the left turn stop/turn circuit. This should activate the left taillight brighter than the running light circuit, and finally the last pin will be the right turn/stop circuit. The same thing as the previous circuit but for the right taillight.
![Jameson C](https://images.etrailer.com/static/images/catg/people/371_tn.jpg)
Products Referenced in This Question
Hopkins Tow Doctor Trailer End Test Unit
- Electrical Tools
- Testers
- Tow Function Tester
- Hopkins
more information >
Featured Help Information
Instructions
Miscellaneous Media
Continue Researching
- Shop: Hopkins Tow Doctor Trailer End Test Unit
- Video: Hopkins Tow Doctor Trailer End Test Unit Review
- Video: Trailer Wiring Harness Installation - 1998 Jeep Cherokee
- Q&A: Recommended Way to Test Trailer Lighting With a Car Battery to a 4-Way Trailer Connector
- Shop: etrailer Boat Trailer Jack w/ Wheel - Sidewind - Swivel - 10" Lift - Zinc - 1,000 lbs
- Shop: Hopkins Endurance Quick-Install 7-Way Trailer Connector - Vehicle End
- Shop: T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Shop: Trailer Wiring
- Search Results: jack swivel
- Search Results: optronics
- Search Results: e~track parts
- Search Results: tow doctor
- Article: Troubleshooting 4 and 5-Way Wiring Installations
- Q&A: Trailer 7-Way Connector Tester Recommendation
- Q&A: How to Power Trailer Taillights Without Being Connected to a Tow Vehicle.
- Article: Trailer Wiring Diagrams
- Q&A: Correct Mounting Bracket For Pro Series Round, Pipe-Mount Swivel Jack PS1401440303
- Q&A: Inner and Outer Diameter of the Replacement Mounting Bracket # TJB-MB
- Shop: Demco Trailer Coupler - Flat Plate Mount - eZ-Latch - Black - 2-5/16" Ball - 21,000 lbs
- Shop: Submersible, Under 80" Trailer Light Kit with 25' Wiring Harness
- Shop: 20 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 30" Ground
- Video: Review of Demco Flat Mount Trailer Coupler - Fixed Coupler - DM69FR
- Video: Hopkins Wiring - Tools for Wiring - HM50918 Review
- Video: EZ Connector to 7-Way RV Adapter Review
- Video: Review of Fulton - Trailer Jack,Camper Jack - P9012-00
- Video: Review of Demco A-Frame Trailer Coupler - eZ Latch Standard Coupler - 12660-97SP
- Q&A: Will a 3-1/4 Hole Saw be Enough for Installing Recessed Trailer D-Ring Tie Down # RR05
- Q&A: What is the Capacity of Buyers Products 5/8 Forged D-Ring 337B40MP