trailer lights aways on- resolution

[Dale M.]

Years of experience dealing with these issues tells me that the trailer charge and parking light wires are in the wrong holes. There is no way for them to wire the truck wrong....all the wires for the tow package are molded in to their respective plugs, including the trailer plug. It's just plug and play. So unless you got that 1 in 1 million that happened to get screwed up you need to take the trailer to the dealer and have them check their wiring. On another note, taking it to the Ford dealer for trailer wiring will rarely result in the desired outcome. I worked for a trailer manufacturer for 20 years and calling any of the major dealers was generally a waste of time, they know very little about the trailer wiring. (no, not just Ford, all of the manufacturers, it's not something they are really trained on) Trailer problems are generally more easily solved at a trailer manufacturer/sales place that has a service department.

Ditto...

Dale

[canonsue]

The plug is a 7 prong. If the trailer battery can "backfeed" then that would make sense of where the power is coming from.

Thanks for the hints. I will check the trailer wiring first. I will also pick up an an inexpensive tester as my last one broke just to see that no power is coming from the truck when key is out and lights are on.

Thanks for the ideas. I will post the fix when I am done.

-Sue

[down under tech]

Hi Sue:

You can check your wiring yourself with a test light you can get from any auto parts store. An inexpensive one is just fine. I think you have a wire that is frayed and a strand of that wire is touching the next terminal inside the (trailer) side plug connector. The 12 volt power coming from the vehicle side of the plug has the tail lights and the 12 volt power, they are side by side inside the plug. I have included a link to the proper wiring of the plugs for the most common plugs used on trailers. I think you have the seven pin (flat-blade) RV style plug. It is very easy to check the plugs this way. Place the grounding clip to a clean metal surface and probe the plug with the pointed side of the tester. The light will come on when power is present. Like everyone has said you will find the trailer side plug is where the problem is. Check the TV first then the trailer.

Link... http://www.etrailer.com/faq-wiring.aspx

[cracker39]

Seems simple to me...truck is the problem. The trailer lights can't be on unless the truck is sending power through the connector. Check the truck.

[canonsue]

Well, not the truck. I pulled fuses in the truck and trailer lights were still on. So I unhooked the power lead off of the trailer battery and the lights went off, so the lights are definitely powered by the trailer battery. All looks good in the trailer junction box, so it does look like a problem in the trailer plug.

Unfortunately, it is a molded plug so I can't open it up and fix but I will test each pin.

However, it is a brand new Little Guy so the fix should come from my dealer. I am just trying to save a 3 hour drive.

Sue

[proformance]

Sue,

Glad you have determined which vehicle is the source of the problem before spending all the time at the Ford Dealer.

If I were you, and I was not fully understanding of trailer wiring and not comfortable cutting/splicing wires, I would chose the three hour round trip back to the Trailer Dealer before I started cutting wires. And, I would insist in a formal and detailed receipt for the warranty work. I would then submit a copy to Little Guy and request reimbursement for your travel/time expense. I'm sure they will not entertain the request, but at least they will know how unhappy you are with the issue.

Also, keep the original receipt for your records in case additional problems begin to arise with the trailer.

[cracker39]

Seems simple to me...truck is the problem. The trailer lights can't be on unless the truck is sending power through the connector. Check the truck.

Well, I've been wrong before. One might get hurt jumping to conclusions.

[eamarquardt]

Gene Kranz: Let's work the problem people. Let's not make things worse by guessing.

We don't have enough data. I agree with the above. That approach got three fortunate men back from the edge of disaster (not to mention, the Moon).

Check for voltages off the truck at the connector, pull the relay and check for voltages at the truck connector, check the operation of the turn signals and brake lights on the trailer. Then you'll have what you need to determine where the problem is. Perhaps a couple of problems.

All you need is an inexpensive volt meter available at HF, HD, Lowe's, or wherever.

Cheers,

Gus

[canonsue]

He friends,
I drove up to my dealer to test more options and it looks like the truck is the problem. The trailer worked correctly connected to the dealers vehicle. We put a tester on the plug of my truck and when the key is turned on both the power to the battery and the tail lights were hot. My dealer showed me on his truck that only the power To the battery should light up.

Somehow there is an circuit that draws power from the trailer battery to the lights when the harness is plugged into the truck. Now I get the fun task of convincing Ford of the problem.

My Little Guy dealer felt bad that I drove up there that he gave me a $50.00 check. I told him that he did not need to do that and especially since the problem was with my vehicle. Let's just say that I am very impressed with his service and with the great price and quality of the trailer.

Sue

[eamarquardt]

First I'd check to see if the battery feed and tail light wires in your vehicles tow connector are somehow making contact. Easy and cheap to do. Seems kinda strange that you're truck's lights don't come on with the key but the trailer's do. Some of the new cars are kinda sophisticated, monitor the filaments in the bulbs (by switching the ground side of the bulbs versus the hot side as used to be the case), and use an "electronic module" separate from your vehicle's lights wiring to drive the trailer lights. A quick check would be to remove the battery charge relay (I think you mentioned one) and see if the problem goes away. If it does, I'd suspect a connection between the battery feed and your tail lights, most likely at your trailer connector on your vehicle. If the problem remains I'd suspect the "trailer light module" if you have one.

Hope this helps.

Cheers,

Gus

[High Desert]

Sounds like Little Guy treated you right, thats good to hear! It also sounds like he found enough proof that the dealer should be able to find the problem. I stand corrected on my first diagnosis, it was based on previous experience. It may be a relay or module, or could be something as basic as a pinched harness done during assembly that just didn't show until a trailer was connected. Hopefully being a 2011 it's still under warrenty. I personally wouldn't touch anything until a visit to the dealer, wouldn't want to void anything by accident. Again, good luck getting it sorted out.

[Miriam C.]

Way to go Little Guy! I second the "don't do it yourself." With a new car warranty you want your dealer to do everything or at least as much as possible.

[canonsue]

I will call the Ford dealer first to make sure that they have a 12 volt RV plug circuit tester. If they do, then it will be easy to show them the problem. If they don't I will see if I can borrow one from someone from work.

I would also like to see the tester on another 2011 F-150. It would be bummer if that is the way that all are wired.

My dealer (Signature Sales in Loveland, CO) is reseller of Little Guy but he did have Scott from Little Guy call me in case there was an easy answer. So again, both my dealer and Little Guy has done well to help me.

-Sue

[pete42]

way to go Lil guy

You could try looking here http://www.etrailer.com/faq-wiring.aspx

did you mean to say 2001 or 2011?

I have a 2001 F150 the relay and fuse you installed is for the battery charging system on your trailer and is off when the truck's key is off.

there should not be any voltage going to your trailer from the truck unless you turn on the lights, step on the brake or with the key turned on the turn signal lights.

99% of trailer lights not working right is caused by a bad ground you may be in that 1% good luck.

pete

[canonsue]

Sorry, i meant a 2011 truck.