QuestionHi again, thanks for your response.
My follow up is:
1)isnt the ground covered via the 4th wire in the flat 4 connector (white).
brown is running lights, green is right turn and yellow is left turn. The white wire I believe is ground, as I am pretty sure that in the car, the white is bolted to the car chassis. This white wire is also the only connector on the flat 4 with an opposite connector pole then the other 3, and vice versa on the trailer side. The white goes from the harness, into the same fuse box that the other wires go into. here, it is maretted with other white wires from the trailer electrical system. I always believed these to be ground. Is that not the case? I am also curious as to why the running lights would work if I had a bad ground, but not the turn and brake lights. All appears fine at the car end of the connector, as I tested with a meter and get 12V for running and each turn, when using the white as ground.
2) I know you said the brake is controlled by diodes inside the controller, but in the end, it must send 12V down each of LT and RT to give the trailer tail lites the appearance of brake lights? as there is only 1 bulb in the back of the trailer lite assembly, with 2 filaments.
3)I can easily replace the controller if that is the problem... shoudl I see 12V coming off the LT & RT on the car end connector when the brakes are applied?
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Followup To
Question -
Hi, I have a tent trailer that is showing some weird behaviour with the tail lights.
My car has a tail lite converter kit, because the turn is separate from the brake. it is a flat 4 pin out. the trailer is same.
from the trailer, the 4 wires enter a fuse box. There are 3, 8 amp fuses here, and also the common wires all come together inside this box. What I am noticing is a few things. 1) trailer never lites up brakes, "running" tail lites are always on, but never get brighter.
2)Left $ right turn dont work. I have tested these right at the car plug, and there is 12V, but by the time the wires enter the fuse box, the voltage is much lower... I dont know why. the wire gauge is 14 or 16 I think. It is a new wire run, so I dont understand what is causing it. Can you lose that much voltage over 10-15 feet? enough that the turn lites wont work? again, the "running" lites are fine, 12V in the box and I see the tail lites lit. 3)and last thing is, how does it work to get brake lites in this situation? should the tail lite converter be sending l&r turn at the same time when the brakes are applied? there are only 3 wires, tail, Rt and Lt...
Answer -
It sounds like you are experiencing a problem with a bad ground, typical for what you are experiencing. You should have a ground wire in the harness, DO NOT EVER rely on grounding through the hitch ball. The brake lights are actuated through a series of diodes with in the convertor. These convertors do have a history of going out.
AnswerYes, you are correct, white is ground, but if you have a faulty ground at any point, this could act the same as not having one at all.
The guage of wire is fine in your case and that short of a distance should make no difference.
When you apply the brakes, you should see 12v at the brake lights on the trailer. This only changes when you have the turn signal on.
This seems to point to either a faulty convertor and/ or a bad ground. Have you made sure the bulbs are correct in the tail lights and that they are installed correctly? It is possible sometimes to insert an 1157 bulb into the socket incorrectly and still get light function however incorrect element to light up.
