Troubleshooting 7-Way to 5-Way Adapter Where Stop/Turn Circuits Arent Active

Question:

Hello, I purchased a 7 way to 5 way flat adapter part# A75TB. I own a 2011 Land Rover LR4 with factory wiring harness. It has a 7 way and a 4 way flat. When I plug in my 5 way flat off of my boat trailer with standard bulbs to the 4 way all the light functions work. When I use the 7 way to 5 way adapter that I purchased and plug in the boat trailer only the running lights on the trailer work. The brake and turn signal lights do not work. I saw that there is a led model of this adapter, but I thought that was for led trailer lights. But wondered if I need that one since the LR4 has led tail lights. Please help. Thanks,

asked by: Scott R

Expert Reply:

First thing you will want to do is use a circuit tester like part # PTW2993 to test the stop/turn circuits of the 7-way you have on your vehicle. It sounds like maybe those circuits are shorted out and that is why it seems like the adapter # A75TB isn't working properly. If this is the case you will want to check the conditions of the wiring on the back of the 7-way as well as check for and clean any corrosion you find on the 7-way pins.

The next step will be to connect the # A75TB to the 7-way and test for voltage on the 5-way pins to see if the voltage isn't making it through the adapter. If so, then the adapter is bad and needs to be replaced.

Since your trailer doesn't have LED taillights you wouldn't need the special adapter # C35FR.

expert reply by: Jameson C