Trailer wiring confusion

[TheThom]

Hello everyone. I'm rebuilding a camper from scratch. I purchased a 7 pin trailer cord w/ junction box
http://www.amazon.com/Conntek-Inline-Trailer-7-Gang-Junction/dp/B004D2I75Q/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1358087450&sr=1-1-catcorr&keywords=trailer+cord+junction+box.


I wired it up color to color (green to green, yellow to yellow, etc). I finished wiring up (most of) my marker lights as well as my tail lights/turn signals. I have the ebay version of these lights


When I went to test it, I got some weird results. None of the running lights come on just from running.

Running=nothing lit
Brakes=marker lights light up (not tail lights)
Left turn signal=nothing lit
Right turn signal=all marker lights blink (not tail lights)

My TV is a 2001 Jeep Cherokee. I bought it used ~3 yrs old and it already had the hitch/wiring. I think it's the factory tow package.

I was going to rearrange the wires at the junction box (I have some clues about how to proceed from the blinking marker lights), but then I realized it might be the TV. I'd hate to get it set up for this vehicle and then not have it work with any subsequent vehicles.

Which do you think is more likely to be the culprit? The wires on the junction box are wrong or the factory tow package/adapter is wrong?

Also it's worth mentioning that I tested the tail lights on a 12V battery and they worked fine.

Any other ideas suggestions?

Thanks in advance. Electrical work is not my bag

[Dale M.]

I have always found the factory vehicle harnesses are usually correct with how they are wired (if unmolested by people) ..... You can verify plug on TOW vehicle with this information below....

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

Also a tool like this is going to be your new best friend ($5 at local auto parts) .....



I do most of my automotive/trailer/lamp wiring trouble shooting with simple tool above although I have many expensive meters and other tools to test with....

First thing is to verify the socket on Jeep is wired correctly (see e-trailer wiring information) by position of terminals on socket....

Next is to plug in pigtail and see of function at end of pig tail matches (by color and function) of Jeep socket... I bet they do not.....

I found when I ordered the molded pig tail (similar to one in your picture) when I did my car carrier the wire colors did not match the "function" of the plug (color/position/terminal numbers)....

I ignored wire colors in pigtail and wired by "function" then wrote new color code for how pig tail was wired to positions in terminal box, which was wired by correct color (trailer side) to all the lamps and brakes.....

Seems that somebody forgot to tell manufacturer of pig tail there is as color scheme already in the industry that should be used but they chose to go with their own.... YEs I did a head scratch for a bit too after first connect by colors only....

Start over by either using a meter to continuity the pigtail (color/position/terminal number) or use a test lamp to figure out what color wire does what function and make a new color code to use when wiring pig tail....

Also think there was some color issues with terminal box (some marking for colors that did not exist) , but plug seemed to be biggest culprit....

Remember color codes are for people..... Electrons are color blind.... Wire for function/position then match color to function ( but follow colors as much as possible) when making your cheat sheet for future reference.....

And on your LED tail lights... Believe White is Ground, Red is Stop and Black is Tail (marker)...

Dale

[TheThom]

Awesome answer! I was leaning toward the pigtail being the culprit. Glad it has happened to others and I'm not THAT incompetent and crazy

[Dale M.]

Let us know what you "discover"....

Dale

[48Rob]

Start over by either using a meter to continuity the pigtail (color/position/terminal number) or use a test lamp to figure out what color wire does what function and make a new color code to use when wiring pig tail....

Always (in my opinion) the best route to go.
Easy enough to test and mark each wires function from the pigtail/vehicle, then wire trailer to match.

E trailer, last time I looked, had an incorrect diagram...

Rob

[Dale M.]

Start over by either using a meter to continuity the pigtail (color/position/terminal number) or use a test lamp to figure out what color wire does what function and make a new color code to use when wiring pig tail....

Always (in my opinion) the best route to go.
Easy enough to test and mark each wires function from the pigtail/vehicle, then wire trailer to match.

E trailer, last time I looked, had an incorrect diagram...

Rob

What diagram are you referring to.......

The 7 Pin RV on e-trailer site matches my Chevy (factory) wiring and also match 7 pin on my Jeep.....





The colors may not be right, but functionally they are correct.....

The 7 pin round (commercial trailer) is different .....

Dale

[TheThom]

Start over by either using a meter to continuity the pigtail (color/position/terminal number) or use a test lamp to figure out what color wire does what function and make a new color code to use when wiring pig tail....

Always (in my opinion) the best route to go.
Easy enough to test and mark each wires function from the pigtail/vehicle, then wire trailer to match.

E trailer, last time I looked, had an incorrect diagram...

Rob

My plan is kind of in the middle - I plan to hook it up to the jeep and test each terminal at the junction box. Since I've already run and connected my wires, hopefully I'll be able to just swap them around in the box. We'll see.

Picked up a low voltage tester for $2.50 today

Thanks for the help!

[48Rob]

I plan to hook it up to the jeep and test each terminal at the junction box. Since I've already run and connected my wires, hopefully I'll be able to just swap them around in the box.

Yes, that is the same as connecting the pigtail and testing function.
Hard to go wrong...

Rob

[Shadow Catcher]

One investment I made was a tester to check the TV plug. It saves a good bit of time and effort finding out why that one light does not work is because it is the TV wiring going south.

[TheThom]

So I was able to map it out.

Black = hot (12V auxilary)
Green= running lights
Red=Left turn signal
Brown=right turn signal
White=Ground (thankfully)
Yellow= Backup lights
Blue = brakes (I think, I still don't have my brake controller installed).

The running lights are working fine, but the turn/tail lights aren't. I'm going to try and give them a better ground and see if that does the trick.

Thanks for all of the help! I never thought $2.50 and 15 minutes would figure it out.

[bobhenry]

I haven't read all the posts........

Has anyone mentioned tow vehicle to trailer grounding ?

With 3 years in U haul 99% of all light problems were quickly corrected by hard wiring a ground from the vehicle to the trailer. As a quick test I would clamp a jumper cable from car frame to trailer frame and if gremlins disappeared I would fabricate a hard ground with a short length of wire.

[Dale M.]

Thanks for all of the help! I never thought $2.50 and 15 minutes would figure it out.

Got to love a simple test lamp....

Also bench test (directly at/to battery) your turn/tail lamps to see if they function properly and that you have color code correct....

Dale

[Engineer Guy]

'Ringing out' all connections - confirming and logging which Wires do what - has always been my first step in Troubleshooting. Then, you know 'what is' vs. what 'should be' from Vehicle or Aftermarket Documentation. The point about confirming Ground is also very important.

When the OEM Trailer Converter/Harness from the Manufacturer [Mitsi] went out after a Decade of service - coincidentally, after I'd had work done on my Utility Trailer - I thought I'd upgrade to LED Trailer Lights from Wally World. I ordered a Hopkins Trailer Harness Converter. It was ~half the price, and a different Model Number, than the one linked below that I eventually had to use. Only after I received the first one was it stated on the Converter [and not in any Product Description or Literature] that 'This Should Not Be Used With LED LIghts'. Say what? They draw ~1/10 the current as conventional Lamps. After a chat with Hopkins, I ordered the one below at ~2x the price. Being larger, it was laborious to fit behind the Taillight. I finally had to tear apart the rear Hatch area and position it elsewhere. Also, it requires separate +12 VDC from a separate source to power the Trailer Taillights. So, I tapped a rear Cig Lighter Convenience Outlet in the Hatch area. What a hassle. But, using an independent Voltage Source to power Trailer Lights, making that wiring more immune to voltage drop, made sense to me.

Common practice is to have some isolation between Vehicle Lights and Trailer Lights. My long-winded point is that, if changing Wiring connections doesn't solve the problem, it MIGHT be that your Vehicle Wiring Harness Converter 'Module' hidden somewhere does not have the capability to operate LEDs. Just as was the case with the first Hopkins Converter 'Box' I ordered.

This was really a weird one for this experienced 'Sparky' to get my Head around. Only assuming 'nothing' and ringing out everything finally made the problem clear enough to solve.

Hopkins Trailer Converter

[TheThom]

AFter grinding some paint down and running a better ground for tail and backup lights, all of the lights on my trailer are fully and appropriately functioning!!

Thank you so much for your help!

Now to make it look like something besides a rat's nest....