7-Way to 4-Pole Adapter Not Functioning When Installed on 2001 Land Rover Discovery II

Question:

i have a 2001 land rover discovery 2. I recently bought a 7 pin to 4 flat adapter. When i plugged it in and hooked it up...the left and right blinkers go at the same time, and running lights dont work. I hooked the trailer up to my friends truck just flat 4 to flat 4 and everything worked the way it is supposed to. Does this indicate somethings wrong with the adapter? Is there something different about the way it should be wired?

asked by: David A

Expert Reply:

I'd begin by testing the 7-way on the Land Rover. The trailer wiring FAQ I've linked you to will show you which pins on the 7-way will show voltage as each turn signal/brake lamp/ running lamp function is activated. Make sure the 7-way is wired as shown in the FAQ. Then, plug the adapter into the 7-way and test each function. If you don't have a circuit tester, we offer one as part # PTW2993.

Usually when you have both turn signals operating at the same time, it indicates a ground problem. You'll want to ensure that the main ground wire from the trailer connector is securely grounded to the trailer frame and that each lamp is grounded to the trailer frame either by a separate ground wire or by its mounting hardware being in direct contact to the frame. I realize the lamps worked okay on a different vehicle, but some vehicles are more sensitive to a poor ground connection than others.

expert reply by: Mike L