F350: How to have trailer running lights on all the time when towing?

[BabyBober]

Hi All:
Maybe this is a simple thing but... I would like to have trailer running lights on whenever I tow without having to manually turn on the truck lights. I have my reverse camera on the 5th wheel wired to the running lights so that it is not always on. I went to leave the truck lights in "auto" instead of manually turning them on and off. Is there a way to do this? Having "daytime running lights" enabled in the user settings of the truck does not accomplish this.

THANKS
Jim

[Cate&Rob]

Jim,

What you are looking for is a signal that indicates "trailer plugged into truck". This is going to be difficult to find because the trailer battery will back feed the 12V connection that you want from the truck that charges the trailer battery when the truck is running. Certainly could be done with relays, diodes and voltage sensing . . . but maybe more complex than turning on the lights when you tow ?

Rob

[BabyBober]

Jim,

What you are looking for is a signal that indicates "trailer plugged into truck". This is going to be difficult to find because the trailer battery will back feed the 12V connection that you want from the truck that charges the trailer battery when the truck is running. Certainly could be done with relays, diodes and voltage sensing . . . but maybe more complex than turning on the lights when you tow ?

Rob

Rob:
I was kind of hoping since the Ford is smart enough to "know" the trailer is there that there would be a "programming way" for the truck to do it. Yea, I could design a "circuit" but that is more trouble then it is worth...
THANKS
Jim

[Cate&Rob]

Jim,

The truck might be smart enough . . . but you have to communicate this to the trailer through the standard 7 wire umbilical . . . which brings up a possibility.

Thinking about this a little further, if you connected the running light terminal in the truck socket to +12VDC feed (red) rather than the running light feed from the truck (brown), the trailer running lights would come on whenever the trailer is plugged into the truck. The trailer lights would stay on (back fed from the trailer battery) until the trailer was unplugged from the truck, even if the truck was shut off.

Rob

[BabyBober]

Jim,

The truck might be smart enough . . . but you have to communicate this to the trailer through the standard 7 wire umbilical . . . which brings up a possibility.

Thinking about this a little further, if you connected the running light terminal in the truck socket to +12VDC feed (red) rather than the running light feed from the truck (brown), the trailer running lights would come on whenever the trailer is plugged into the truck. The trailer lights would stay on (back fed from the trailer battery) until the trailer was unplugged from the truck, even if the truck was shut off.

Rob

Thanks Rob, I could build an "adapter" plug to trick the system.

[Cate&Rob]

Thanks Rob, I could build an "adapter" plug to trick the system.

That's an even better idea .

[theclarks]

Hi All:
Maybe this is a simple thing but... I would like to have trailer running lights on whenever I tow without having to manually turn on the truck lights. I have my reverse camera on the 5th wheel wired to the running lights so that it is not always on. I went to leave the truck lights in "auto" instead of manually turning them on and off. Is there a way to do this? Having "daytime running lights" enabled in the user settings of the truck does not accomplish this.

THANKS
Jim

What I've done in my Chevy's was cover up the "sensor" on the dash. The "daytime running lights" don't bring on the "tail lights" and I want to be sure I can be seen from the front as well as the rear. I started with a ball cap over the sensor but that covered the defrost vents, now I've got a 1" nut with a knock out from a electrical box painted black, works great and my lights are always on. . . . .

[BabyBober]

What I've done in my Chevy's was cover up the "sensor" on the dash. The "daytime running lights" don't bring on the "tail lights" and I want to be sure I can be seen from the front as well as the rear. I started with a ball cap over the sensor but that covered the defrost vents, now I've got a 1" nut with a knock out from a electrical box painted black, works great and my lights are always on. . . . .

Thanks. I will look into that, the only issue I see is that would make the dash very dark and potentially unreadable in the daytime....

[TucsonJim]

Jim - On the trailer's umbilical, put a switched jumper wire between pins 3 & 4. This will supply +12V to the tail lights and running lights any time you turn on the switch.

Jim

[Paul & Deb]

In my GMC I merely turn on the fog/driving lights and my trailer lights come on as well.