Turn signals on travel trailer

[Jameskirk]

I have a 2013 passport TT being pulled by 2009 expedition. When TT is connected to expedition with headlights on the TT lights work fine except when using turn signals which dim when in use. But only when expedition lights are on. Dealership tested with a control box and said it is an issue with expedition. Does anyone know what might be causing this? Thx


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[Bluewater]

If I recall correctly it may be something in the headlight switch. Maybe they have an update now.

[hankaye]

Jameskirk, Howdy;

Might could be the flasher unit up under the dash... isn't strong
enough to work ALL of those lights... just my best guess.

hankaye

[cabinfever]

Could even be a bad bulb turn in the TT or TV. The bulb may still work but have a problem. I had this happen on our car. A taillight was still working and looked fine but something was wrong with the bulb and was causing a odd flashing pattern when turn signals were on.

[hankpage]

What happens when you step on the brakes?? I'm not sure about Ford but I think an '09 uses computer instead of flasher. Check the grounds on both TT and TV. Look closely at trailer bulbs to see what filament is lighting when brakes are applied, taillights may be wired backwards. Dealers tester is using trailer's 12v not TV's ... check voltage out from TV. JM2¢, Hank

[hankaye]

Jameskirk, Howdy;

If your RV's tail lights are the automotive bayonet style
they may have been installed backwards, so the shorter
low power is lit instead of the tall high power one. if the
lights dim when you step on the break and they dim is
the best indication. Thanks to the 'Other Hank" for knocking
some more dust off the gray matter...

hankaye

[Jameskirk]

Thanks everyone! When applying the brakes the lights dim as well. You all have given me several areas to look at. Thanks!!!


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[Jim & DJ]

Sounds like ground, weather battery or light plug.


PLEASE LET US ALL KNOW WHAT YOU FIND OUT.

[RdRmr]

Jameskirk, hello. Had somewhat the same issue with my 2011 Cougar High Country. Keystone had reversed the polarity of the 12V wiring to the right rear tail light during manufacturing. It worked fine as long as I didn't turn on the headlights in the tow vehicle. Turn the lights on and everything would go south. Would have no right turn signal and the running lights would pop the fuse in the tow vehicle every time I turned the head light switch on.
Just an FYI. Happy Campin....