Problem with Interior Trailer Lights
 

Hi Everyone, not sure if this is posted in the right section, but I was hoping someone could help. I have a 2009 Chevy Tahoe with a full trailer package and 7 pin wiring harness. Also have an enclosed Thule Snowmobile Trailer. Everything (exterior lights, electric brakes) works great when I hook it up to the truck, but the interior lights are not firing up. It's almost like they are receiving no power at all. Is there a fuse I need to add somewhere? The manual is not very helpful. Seems like there should be a simple fix. Any help would be appreciated. Thanks! :)

The light fixture inside these trailers are not very well made. I have had this same issue on more than one trailer I own. If you have checked the obvious with a test light(light bulb, power to wire, etc, etc), the switch itself in the light fixture may be the problem. The slide style switch was the issue in my Sno Pro trailer as well as my Haulmark MC trailer.

Hope this helps.

Dan

three things to check
 

one - there is usually a junction or control box at the tongue near the battery that runs the break-away brake. Check that the interior light wiring is connected to the appropriate terminal (and that terminal has power).

two - if there is an internal switch for the lights - make sure you know that it is on (both my horse and snowmibile trailers have this).

three - make sure that the truck lights and/or accessory position is selected or 'on' if either is needed to run the lights. My snowmobile trailer (Kristie) requires that the parking lights be on for the interior lights to work and the horse trailer (CM) requires at least the accessory position on the ignition switch.

i'll bet one of these is your problem.

Looking at your truck plug from the rear make sure the terminal in the 0100 position has batt current. This feeds lights batterys and whatever needs you might have. If it is dead remove the "full" cover from the underhood fuse box. Sometimes they are not hooked up. Should be connected to the rear lug and have a 30 amp maxi in the box for the line. The Featherlites we carry never run accesorys from anything but that line.

Attached is a picture of that 7 pole connector on the trailer that goes to the truck. As dog paw said make sure the fuse is in the truck feeding battery to the receptical. Some trucks only have voltage at the connector when the ignition is on. A common problem with lights in a trailer is a bad ground at the light fixture.

Trailer lights
 

Is the bulb any good ?

A little off topic...
On my Ford Expedition, relays also need to be in place and working for some pins to have power. It took me three trips to the dealer to convince them that Ford did not supply my truck with the relay needed to power the backup pin. Most users probably never use it so they left it out of the standard towing package. I finally got a service technician with more curiosity than opinion to pull out the electrical drawing and trace the problem. Sure enough, no relay in the socket.

Right on RISY. My 99 F250 fires up those 2 lamps in our 32' SnoPro Trailer (Thule) only when the truck is running or at least the key is turned on (not accy). It is probably a good idea or there would be many dead batts.

DC, I am in Moultonborough. If you need help with trailer wiring (or 12V in general), PM me and I will help you out. I used to do it for a living, now it is just fun.

In my experience I have found that most electrical problems end up being a poor connection. FWIW, take a bit of emery cloth or even fine grit sandpaper to all the connection points. And check and make sure that the ground is good. Good luck.

Thanks everyone for the suggestions. Just got a chance to look at this. There is definitely no power to the terminal (at 1 o'clock) and all the exterior lights, electric breaking system work fine so there shouldn't be any grounding issues. I am having trouble locating which fuse is responsible for powering up this terminal in question. I read every fuse description under the fuse cover box and can't figure where to add the the neccessary fuse? Maybe I am doing something wrong. There are definitely more areas for fuses than are represented on the fuse location/description schematic. Any further advice would be most appreciated!

Usually the fuse that feeds 12 volts to the connector is under the hood, not located with the fuse panel that feeds every thing else. You can try searching near the battery or the computer under the hood, I don't recall where Chevy puts it.

Most likely the 30 amp fuse that supplies this circuit is already installed in the large accessory fuse box you've found under your hood. Usually the factory installs the fuse but does not connect wiring associated with pin 1 of your receptacle to the + terminal at the box. Each model is different, but you may also want to check for a gray, or pair of gray wires with ring terminals already installed but not attached to the associated terminal.

These wires are normally left disconnected and not usually referenced in the owners manual as the dealer wants you to have him do the hookup. These wires are normally hooked up by the dealer or an aftermarket installer when you have an electric brake controller installed. I don't recall if you indeed have that option installed as either a dealer or aftermarket installation.

The fuse you are looking for associated with this option is a green 30 amp type.

Could still be a lot of other things as previously mentioned here, but give that a check if you can! :)

Its not a fuse thing, ya just have to hook up the wire. I found this on boob tube

http://www.youtube.com/watch?v=fCiibxiKJQ8

around 3:50 it give a quick shot of hooking up the accesory feed wire to the hot post on the fuse box :)

That video is for the electric brakes. Most new vehicles now have a modular connector under the dash for the brake controller, particularly if they come with the factory towing option and a pigtail in a bag in the glove compartment to hook up to your brake controller.

DC Pointer is looking for the 12 volts that feeds the interior lights and battery in the trailer. Most people on the camping forum I visit say the 12 volt wire comes connected to the fuse block under the hood but usually the 30amp fuse is not installed.

I will gladly look at it with you- drop a PM.

Yes it is, but like I said @ 3:50 he quickly addresses to untape the "assessory feed wire" and attatch it to the post next to the brake controller wire. But anyway what do I know...

I have the same exact problem with my 2004 Snopro trailer.
Did you figure it out yet?

I will add again that unless your ignition is on, often times the auxiliary circuit has no power. It is like this so you do not discharge your batteries accidentally.

So before you pull your hair out, try the lights with your tow vehicle running.

It's in the trailer
 

I used to sell Sno Pro THule trailers. Call your local dealer, it's in the junction box you have to switch a wire, I don't recall which color, memory says Brown, but call a dealer, happens all the time.

You solvled the problem! I had the same exact problem as DC Pointer.
I attached the 12 volt wire to the post as it shows in the video and
installed the fuse. The interior trailer lights now work.

dog paw,thank you very much!

raydoe1

I had the same exact problem with my 2010 Chev. Silveraldo
and my 2004 SnoPro Trailer.IT is in the vehicle, not the trailer.
Watch the youtube video as dog paw suggest.At the end of video it,
it shows you how to attached the 12 volt wire to the post on your fuse box.
Its very simple, it only takes 5 minutes to do, but you have to buy a fuse and
a nut to attach the wire to the 12 volt post.