Backup Lights Stay On (Help!)

[pscottn]

The backup lights (the clear, middle lights on the rear of the trailer (1979 AS Ambassador 29') stay lit when the trailer is connected to the tow vehicle 7 prong electrical plug. All the other exterior lights turn on and off as intended. What keeps these two clear lights on all the time? Any ideas. Appreciate any solutions.

[thenewkid64]

If you check, I bet the wire that is coming off your tow vehicle for the 12 VDC feed to the trailer is wired instead to the backup lights.

There were a number of diffrent wiring configurations on the diffrent Airstream vintages.

It is more than likely that the backup lights and 12VDC feed need to be swapped in your pigtail connector.

The best way to check is with a volt meter or test light and a helper.

Wiring diagrams can be had from the Airstream site.

[Coloradobus]

pscottn

We found when hooking up '03 Discovery and '67 Globetrotter, that the cars hot wire corrosponded to the trailers backup lighting.
Seems older Airstreams wiring diagram for lights is different than what is use today. All the other light worked. However we also had no brakes.
Turned out the brake wire corrsopnded to a blank on the car. Moved the trailer's brake wire to the same position as car, bingo we had brakes.
For the time being, the car is not wired for baclup light in the plug, so we left it blank.

[Pahaska]

There is really no enough information in your post to pin it down; however if they are on with no other lights on, it could possibly be the tow vehicle, a miswired umbilical plug, or a short between the battery charge line in the umbilical and the backup light line.

Does your trailer, perhaps, have the old Airstream wiring of the umbilical plug? If so, that could very well be the problem. Go to the Airstream site and look at the bottom of the page for links to all the various umbilical wirings used through the years.

[dtbw]

The backup light connection is the center one (#7) and the screw lug on the backside is VERY close to the battery charge connection (#4) & the running lights (#3). If the backup lights are on regardless of whether the running lights are on, then the short is to the charge line. I HIGHLY suspect that the short will be found inside the connector where the wiring connects. You can easily check to see if the tow vehicle side is the problem with a 12V continuity light. These can be found at any auto store, or you can use a DC multimeter. The whole idea is that the CENTER contact within the connector on the car should NOT active (ie 12V present) except when the tow vehicle is in reverse. If the center contact seems to be working properly when the trailer is disconnected (ie no power to center contact except when vehicle is is reverse...don't check it with the engine running...safety factor) then the short is most likely on the trailer side, but it still could be a loose contact on the vehicle side that shorts only when you plug the trailer into the tow vehicle. Either way, a good visual checkout of the connections on the backside of the connector should be done before looking elsewhere. Hope this helps