Troubleshooting Wiring for a 1998 Ranger Trailer 7-Pin Round to 4-Flat on a 2011 Chevy Tahoe

Question:

the adapter I have takes my 7 pin round and converts to a 5 pin flat, my trailer has a 4 wire flat. when connected my running lights work fine but turn signals and brake lights do not work on trailer, do I need to get a 7 pin round to 4 pin flat or an extension. simply put does the 4 pin flat need to be connected via 4 pin- 4pin is that why 5 pin doesnt activate the turn/brake lights?

asked by: Blair H

Expert Reply:

There are a couple of potential issues as to why your turn/brake lights aren't working. First you will need to determine where the problem is coming from and to do that test the vehicle side of your trailer connector.

Use a 12V circuit tester like # PTW2993 to check the function at your 4-way plug such as # HM48110. Having a friend sit in your 2011 Chevy Tahoe to engage each function while you test. If functions are good, test the 1998 Ranger trailer because your 4-way will be okay. If signals are not good, check for blown fuses and or relays.

Secondly, check the truck and trailer side connectors are clean and free of corrosion. On the trailer side ensure the main trailer connector ground and the grounds for all the lights are attached to a clean and corrosion free bare metal surfaces. If your trailer has a tilt bed, folding tongue or aluminum frame those can cause ground issues. Running jumper wires from the light grounds to the main trailer connector ground or axle can help.

You can use a 4-way and plug into a 5-way just fine. You can also use a Pollack 7-pole round pin to 4-pole flat wiring adapter # PK12742.

I included a couple helpful articles for you as well.

expert reply by: Chris B