Troubleshooting Hopkins 7-Way Trailer Connection for Fix or Replacement

Updated 05/04/2018 | Published 05/03/2018

Products Featured in This Question

Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps

(314)

$47.15

Dielectric Grease for Electrical Connectors, 2 oz.

(1508)

$9.54

Hook Probe Circuit Tester

(70)

$13.94

Question:

I had the trailer dealer install a 7 pin/4 pin combination unit on my truck.they installed a Hopkins unit and it has been nothing but trouble. My horse trailer factory plug never fitted like it should and lights didnt work. I took truck and trailer and tech said it was a bent pin. Now I plug it in and the same problem. With the 7 pin round plug the signal lights work but when I turn on running lights they dont work and the truck backup lights are on. How do I check for bent pin as the unit is sealed? All the pins check good with a tester. Everything works on the 4 pin flat plug. I am thinking just get another brand and replace the plug. Any suggestions?

asked by: David M

Expert Reply:

The Hopkins brand connectors are normally pretty good. All trailer connectors can have issues with connections like this due to corrosion or moisture in the connection. I recommend using some sand paper to clean the pins and then use dielectric grease # 11755 to keep moisture and corrosion off the pins. A bent pin is an issue if it keeps bending because it weakens and can cause a connection issue. Normally when a function doesn't work, it is a ground connection issue, and I recommend ensuring your ground contact is bare metal to metal and free of corrosion or debris. I recommend using a circuit tester like # PTW2993 to confirm a solid ground for all functions. When another function has power when it should not, normally that is due to corrosion causing a bridge between pins and cleaning is the best fix.

If you decide you want another brand, I recommend the Curt Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps # C57674.

expert reply by: Jason S