Got a question that is making me curious. When you turn on the key obviously the trailer charge wire in the plug goes hot, but how can I make this go always hot. The only reason I ask is I'd like to plug in a strobe light to the camper hookup in the truck bed, which is wired to go through the trailer plug in the back of the truck I have.

This is only for one weekends use while doing traffic and parking lot control, is it as simple as getting a different relay or jumping accross the relay in the fuse box? The strobe draws 3 amps when it flashes, so it isn't going to run down my battery for the little bit of time my truck won't be running.

Now I know that the obvious thing here is to plug it into the cig lighter, but I don't want to do that when I have a plug-in so handy and close in the truck bed.

Thanks!

 

Ford doesn't like people to loose the capability of starting their trucks if they leave the traielr plugged in so they have a switched auxillery 12v hot. Many trailers with electric brakes have charging systems for the electric break-a-way systems and these can potentially kill your truck battery if the trailer is left plugged in...but only if the auxillery trailer plug is always hot.

To answer your question as to how to get the auxillery always hot you will need to run a fused wire from your battery to the trailer plug. It is easier to run a temporary wire to your cig lighter...which is a fused source.

The wire you will be tapping into at the trailer plug is the orange (1991-current) or red wire depending on the year of your truck.

 

Or, now that I have been playing around with my multi-meter, you jump pin 30 to pin 87 and your trailer plug goes +12 all the time. Exactly what I wanted, and the 30 AMP fuse in the box is still in use, the relay sits in the glove box until I reinstall it later.

I used 4 inches of 10 GA wire and two male plugs (if that is what they are called).

Keep in mind this is only for two days use here in a couple weeks. I won't be leaving this jumped all the time, I feel that ford has a reason for doing what they do and relaying the +12V on the harness, therefor the relay has been reinstalled until that event weekend comes about.

 

I'd have left the relay in & used an illuminated switch to force the relay to stay on. The light in the switch would remind you to turn it back to "normal" when you leave the traffic job.