Intermittent trailer turn and stop lights
Posted: Thu Nov 08, 2012 2:59 pm
Just wired a 4-pin trailer harness into my 95 Pathfinder. Everything works fine on my Chevy pickup, but on the Pathfinder, I get:
1. Running lights and tail lights work.
2. Turn signals and brake lights work sometimes.
3. There is power to the light sockets on the trailer. That is, a test light flashes when turn signal switches are on, and test light comes on when brake is depressed.
4. If I disconnect bulb pigtail and then plug it back in. Turn signal on that side will work. If I turn light off and then restart it, bulb won't light. This is true on both sides of the trailer.
5. I've tried this with a ground running straigt to the chassis to see if ground was inadequate.
6. I've gone through this sequence several times, always the same. I always have power right to the bulp.
To me, it seems that the turn/brake circuit is building up some kind of resistance or capacitance when you turn the working light off. Won't work when restarted. If pigtail is disconnected, the resistance/capacitance, whatever, is discharged. None of this makes sense and I really don't know what I'm talking about at this level. The pigtail is just a pigtail, wired directly through--no fancy components. And even when the bulb dosesn't light, I have power to the bulp connectors within the socket with bulb out. I thought I might have strange/bad bulbs. Its a Swedish trailer. But new ones operate the same. How can I have power to the socket and yet have the bulb flash bright sometimes and fial to flash another?
1. Running lights and tail lights work.
2. Turn signals and brake lights work sometimes.
3. There is power to the light sockets on the trailer. That is, a test light flashes when turn signal switches are on, and test light comes on when brake is depressed.
4. If I disconnect bulb pigtail and then plug it back in. Turn signal on that side will work. If I turn light off and then restart it, bulb won't light. This is true on both sides of the trailer.
5. I've tried this with a ground running straigt to the chassis to see if ground was inadequate.
6. I've gone through this sequence several times, always the same. I always have power right to the bulp.
To me, it seems that the turn/brake circuit is building up some kind of resistance or capacitance when you turn the working light off. Won't work when restarted. If pigtail is disconnected, the resistance/capacitance, whatever, is discharged. None of this makes sense and I really don't know what I'm talking about at this level. The pigtail is just a pigtail, wired directly through--no fancy components. And even when the bulb dosesn't light, I have power to the bulp connectors within the socket with bulb out. I thought I might have strange/bad bulbs. Its a Swedish trailer. But new ones operate the same. How can I have power to the socket and yet have the bulb flash bright sometimes and fial to flash another?