Troubleshooting 4-Way With Constant 12V Power and No Lights When Connected

Updated 01/27/2026 | Published 08/22/2024

Question:

Hi. About 10 years ago I bought for my 2010 RAV4 a Curt tail light converter to flat 4 - same or similar to this one: C56165 In the process of adding on and testing a 7 pin adapter and brake controller, Im finding that all three of the flat 4 outputs are 12V on my voltmeter and unplugged from the 7 pin adapter There was nothing in the add-on that mixed with the 4 pin device, other than tapping the existing 12V feed from the battery to also send into the 7 pin. But then plugged back into my pop-up camper with the flat 4, Im not getting anything to light, running lights or brake/turn. So thats a head scratcher. Perhaps the outputs float high until they have a load on them? Anyhow, Im guessing the converter has simply gone bad and needs replaced. But just thought Id check for any suggestions in case I overlooked something. Thanks.

asked by: Mark M

Expert Reply:

Hi Mark; I see you went ahead and grabbed the # C56165 to replace it which was probably the best choice. The fact that you have constant 12V at the 4-way pins but no power running to the lights is very odd. It could be a bad ground so that is something you might want to check before you proceed with the new installation, but it is probably a bad converter like you said.

expert reply by: Robin H

Robin H.

1/27/2026

Hey Mark, how did things turn out after you replaced the Curt tail light converter on your RAV4? Did checking the ground or swapping the converter get your trailer lights working again? Your update could make it easier for others running into the same issue.