Trailer lites help please.

[davesfriend]

I have an 07 suburban LTZ with a 2000 E-Z loader trailer. I pluged it in and all the lites work except for the turn signals. It has that huge 7 or 9 pin do hickey connector. If it were the four it would be easy to figure out or jump a wire. Does this sound like a fuse in the truck, possible ground on the trailer, or even a bulb? I know it is very difficult to diagnose on the computer, but has anyone else had this problem? Thank you..

[Sandmannd]

to tell if it's a fuse on the truck, unhook the trailer. do your signals work then? If so, I don't think it's a fuse. Could be a ground. I'm not sure with the 9 pins, I've only done the 4.

[davesfriend]

I will have to try that, you see I am heading for Lake superior at 6am friday morning, so I am going to be kinda rushed to get everything ready. Thank you..

[Shack]

DF,

It should be a 7 pin connector.

What I would do is take a test light, connect it to a good ground on the hitch its self and probe the terms inside of the connector on truck. There should be a diagram on the outside cover of the little flap that will tell you what each term if for. Turn your ign on and flip the turn signal to on side or the other. Probe correct term for signals and see if test light flash's. You can probe each terminal, looking for the flashing test light if you do not have a diagram on the little flap cover.

Now, if flashing occurs it is an issue with the trailer. Start to check grounds and what not. If you have the L.E.D. style lights, I believe the whole housing must be replaced. If it is a regular bulb style, then just replace the 1157 or what ever style bulb you have.

Now, if no flashing on test light occurs, 99.9% of the time you have a blown fuse. I am sure it is the same on 07 Chevy's, but the fuse box (power distribution center) under the hood should hold trailer fuses. The owner’s manual should direct you to the correct fuse slot.

Now if the fuses are good, then it could be that connector on the rear of truck or a wiring issue.

Most likely it will be a fuse. The manufacture on newer models must put on trailer light(s) functions on separate fuses from the trucks lighting. The reason why, is because if you have a wiring issue or ground issue on trailer, you will not loose you lightage on your truck.

Good luck this weekend.

[Sandmannd]

I was just going to say all that before Shack, but I didn't want to steal your thunder.

I have redone my wiring on trailers and troubleshot it, but I'm no expert by any means. Unplugging the trailer worked for me. What Shack wrote is a lot more in depth and more worth your while in my opinion. He's someone who knows what he's talking about.

[john.wells]

It could also be an incompatible wiring situation. The newer vehicles use separate brake and turn signal terminals at the connector, whereas older vehicles incorporate the same terminals for brake and signal lighting. If you check the terminals as Shackbash described, and there is working flashers, I would suggest having a friend with known working lights on an older vehicle try hooking into the wiring to eliminate or pinpoint the trailer wiring. If the lights on the trailer work fine, and everything checks out on your truck, you may need to add another set of lights at rear for signals. Do you have the adapter from the 7 pin that reduces to a four pin, or are both connectors (truck and trailer) 7 pin?

[davesfriend]

Wow, you have made this a very simple procedure. Thank you for the info. This will really help out ALOT> Now, is there anyway to make the weather on Superior chang? Thank you alot..

[davesfriend]

That's just it, it worked just fine in the fall. It almost has to be a fuse in the truck. During the winter I pluged in my utility trailer to haul the four wheeler, that trailer has had lite issues before. This may have done it. The e-z loader has encapsualated lites, so if I do have to change a bulb it will be easy..

[john.wells]

With a known problem on your utility trailer, I would say more than likely it is your problem. It is kind of strange that both would be out, though. But, strange things and electricity go hand in hand. It is good to know that it has worked in the past. I didn't know if you had just got the trailer or truck recently.

[john.wells]

Problem pointing to a fuse, that is.

[Shack]

If it was a ford, I would say it would have to be 2 fuses. One for the right trailer turnsignal and one for the left trailer turnsignal.

I am almost positive on newer Chevys, the trailer light turn signal fuse handles both right and left. But, check for two fuses blown.

I was going to also add, once you replace the fuses, that is not the cure all fix. Why did the fuses blow????

It sounds like you answered that question with the 4 wheeler trailer.

Good luck.

Hey Sand!

I really have no idea what I am talking about, I just act like it on FM.

Just doing my part here on FM, but believe me I have been blown out of the water a time or two.

[davesfriend]

I got the truck and boat trailer same day. The utility trailer I have had for some time now. I used to pull that with a windstar. Every time I pluge it in it would not work till I drove a ways, so that had to be the toung ground issue. This could have taken out the fuse in the sub. This will be the first thing I check tonite. Again thank all of you for your help. it really means alot to me..

[Jeremy airjer W]

Fuses first, if that checks out then check for power at the connector. If there is power there check for power out of your adapter. I don't recall reading that you mention specifically if the brake lights worked or not so the adapter is a possibility. One of those three will likely take care of it.

An easy way to check the trailer is to grab any 12 volt battery. Use jumper wires to hook the ground up to the one female terminal on the trailer plug and then the positive to each of the three remaining male terminals one at a time. Check to see if the lights are working for each terminal. Green is the right side brake and turn signal, yellow is the left side brake and turn signal, brown is the running lights, and white is the ground.

7 way plug diagram

[Sandmannd]

 Originally Posted By: davesfriend

That's just it, it worked just fine in the fall. It almost has to be a fuse in the truck. During the winter I pluged in my utility trailer to haul the four wheeler, that trailer has had lite issues before. This may have done it. The e-z loader has encapsualated lites, so if I do have to change a bulb it will be easy..

I had a problem this weekend. I pulled my utility trailer and something shorted. Didn't notice it. Hooked the boat up and gone home to unhook it and noticed the wires were burnt up. Had to put new lights on the utility trailer and new wiring harness on the boat. Chances are if you had problems, something got mess up using that even a fuse. I doubt you have this, but in my case it's been the adaptor to make it 4 pin. Not sure if you use an adaptor for anything but that's another place to check.

[Hookmaster]

I had this issue last spring but only one turn signal didn't work. I didn't know about the separate fuses for the turn signals at the time. I checked the 7-pin outlet with a voltmeter and found that the one that was for the turn signal that wasn't working wasn't conducting any elctricity. I took the 7-pin outlet apart and found corrosion in it. Cleaned it and put it back together and the signal light still didn't work. Then I learned of the separate fuses and found that the one protecting this circui was blown. I replaced it and the signal light worked. The corrosion most likely caused the fuse to blow. This was on a 2004 Silverado.

[Roofer]

That 7 blade can get corroded very easy on any truck. They mounted down where the salt and sand is in the winter and rarely get cleaned or greased. Being it is on two trailers it may be the truck that is the problem, even though it is an '07. The 7 blade connector comes apart on the truck from the back of the little metal mounting plate. Take it apart, inspect, and if nothing is broken, fill it with grease and put it back together.

I had this problem on my 2500HD. The blades on the back corroded enough to break off. This happened on my electric brakes.....no good. The new 7 blade connector was $84, so whether it is the problem or not, get it cleaned and greased. I have some pictures if I can find them.

[davesfriend]

Thank all of you for the help. It turns out that last time I replaced the bulbs the o-ring on the capsules was not seated correctly. I got water in there and instead of light bulbs I had little pieces of glass everywhere in there. New bulbs, set the o-ring correctly, and had an awsome time on Lake Superior!!

[Jeremy airjer W]

Guess we might have over thought that one! Go figure, its the bulbs! lol!!!