View Full Version : Trailer wiring problem

Stuttering Stan
07-25-2009, 07:08 PM
I have a 16ft enclosed Haulmark. The inside dome lights only work when the truck is running. I'd like them to work when truck is off. Any ideas on where to start.

07-25-2009, 07:52 PM
find the wire and plug it into something that is always hot. Use the process of elimination to find it.

07-25-2009, 07:53 PM
I would put a fuse in the line some place.

07-25-2009, 11:26 PM
On your truck plug, there probably isn't a steady hot wire. you would have to find a hot wire or run one from your battery to the back of your truck. Your truck plug may or may not have an extra plug for a hot wire. You would then have to pull the wire from your interior light out of your trailer plug, and hook it up in the corresponding plug slot. Another option? Wire your interior light(s) to an accessory battery (like a deep cycle marine battery). You can mount the battery on the tongue, or in the trailer somewhere...it doesn't take much room in a corner. This is by far the simplest solution, and very effective.

Horsepower Lawns
07-26-2009, 11:41 AM
You didn't say but I would bet $$$ you have a Ford.
If you just pull the relay (Ford changed the location through the years, look in you book) & install a jumper wire into the relay slot you will have your hot wire you want.

The jumper goes into the slots that are like this. | & -- if you put them into the slots that go | & | you will blow the fuse.

Stuttering Stan
07-26-2009, 12:32 PM
Thanks ladies. I do have a Ford, 2001 F250. There are several relays in the fuse box. Could you provide a better description? Why did Ford put a relay rather than a jumper?
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Horsepower Lawns
07-26-2009, 03:17 PM
You will need to look in the owners book and see what one it is.
I think its under the hood on 01s.
If you post a pic of the fuse box I may be able to tell you what one it is.

Ford did the relay because someone leaving a light on will not drain your truck battery, with the jumper in place if someone leaves a light on it will drain your battery.