Electrical light issue on T@da — Resolved!

Carolyn

We have a 2009 T@da. When the vehicle lights are on or on auto the trailer lights are on but turn signals and brake lights don’t work. When the vehicle lights are off the turn signals and brake lights function correctly. We know it is a problem with the trailer as our other trailer works correctly with the same tv. I assume it is a short somewhere but have no idea where to look. Do any of you electrical gurus have any thoughts?

(Subject Line changed to help with search function—Verna, T@B Admin)

pthomas745

Try cleaning the contacts on the 7 pin plug on the trailer and the tow vehicle.

Tundra57

Grounding from the TV to the trailer anf lights is the problem. Make sure traile plug contacts are good. Also ground connection to TV and ground connection from 7 pin plug to trailer chassis. Then ground connection to lamps. If it uses the trailer chassis as ground, cleannup all bolted connections. Wierd light function is almost always a bad ground. Same issue with lamps on Autos.

MuttonChops

Agree with @pthomas745 start but confirming primary connections are clean and tight.

Expect T@DA is similar to other travel trailers and has a Junction Box (terminal strip) that connects the incoming 7-Pin Cable to the trailer wiring.  Most likely the Junction Box is mounted to the frame in the forward a-frame area . . . 7-pin cables tend to be ~10 feet long.  Open the case and check/inspect there if cleaning plug does not solve the issue.

Typical Trailer 'traveling lights' wiring diagram.

Warning:  Colors Shown Do Not Follow Industry Standard 7-Pin Wire Colors

Bayliss

@Carolyn, is there any possibility that water got into your seven-pin plug?  This can happen during storage of the trailer.  Something easy that you can try first is to buy a spray can of electrical contact cleaner from an auto parts store and spray that inside both the plug and the receptacle on your tow vehicle.  Just follow the instructions on the can.

Carolyn

thanks for all of your replies. We did check the junction box and found some suspicious things. There is a yellow wire not connected to anything and a blackmconnected to white and white connected to black. A previous owner had put a new 7-pin cable on and done a strange job of connecting it. We will need to have someone look at that junction box.

MuttonChops

@Carolyn ; Note colors shown in my June 30th trailer wire diagram are not industry standard, believe diagram has colors selected at random.  Have added warning to that post.

The No Connect Yellow Wire from your 7-Pin is most likely the tow vehicle backup lights which is not used on our trailers.  Different connector diagrams will describe the signal/wire as " backup / reverse / center auxiliary ".  It is the center pin of the connector, pin # 7.

Just looking at pictures your Junction Box connections appear correct based on color matching.  Black & White together is normal; 7-pin Black is 12VDC, white wires from trailer are most commonly battery positive and convertor 12VDC.
Space is appears clean & dry . . . most likely not lights problem source . . . have you tried drying/cleaning the 7-pin ?

==============

Ideally you should use a multimeter (ohm meter) to confirm your 7-Pin wire colors.
This diagram uses industry standard colors.

Carolyn

We replaced the seven pin connector in an attempt to solve this. Is there anywhere else you can think to check?

ontheroad

We had a problem with our trailer and the lights...who knew there was a fuse under the hood in our tv that works with the seven pin connector...I didn't mention it before since you said you had another trailer that the lights worked with...we replaced the car's fuse and we had turn signals and brake lights...

MuttonChops

Carolyn said:

We replaced the seven pin connector in an attempt to solve this.
Is there anywhere else you can think to check?

Carolyn said:

We have a 2009 T@da.
When the vehicle lights are on or on auto the trailer lights are on but turn signals and brake lights don’t work.

When the vehicle lights are off the turn signals and brake lights function correctly.

We know it is a problem with the trailer as our other trailer works correctly with the same tv.

Let's step back for a moment.

A]  Have the T@da lights worked in the past for you with this TV?
   Or is this a new to you trailer and the very first time you have checked the lights with this TV.

B] Since starting this investigation have you reconfirmed your other trailer still functions correctly?

If A] is No and B] is Yes,
maybe the last owner has crossed some wires (will need thinking time as to what could be crossed)

If A] is Yes and B] is Yes,
have you done anything to the trailer lights yourself; added one, switched to LED, changed a bulb.  Anything that points to an area to revisit.

Carolyn

This trailer has had this problem since we purchased it. I do know that the previous owner replaced the 7pin and cable. Yes the other trailer works fine with the tv. We did replace the taillights with new led lights because the old ones were very dim (maybe part if the problem). We feel like it must be a ground problem but don’t know where else to look.

Bayliss

@Carolyn, this is a real head-scratcher!  This may not be much help, but I am just throwing out the following as part of the trouble-shooting process:

Returning to your original post, you wrote:  "When the vehicle lights are on or on auto the trailer lights are on but turn signals and brake lights don’t work.  When the vehicle lights are off the turn signals and brake lights function correctly."

Based upon what you have described, it seems unlikely that changing out the trailer tail lights is the issue, since they work when your tow vehicle lights are "off."  Something about turning the tow vehicle lights "on" is cutting off (shorting out?) the power to the turn signals and brake lights.  Very odd.

The left side brake/turn signal lights are wired separate from the right side brake/turn signal lights.  Additionally, the tail lights and running lights are on totally separate lines, so they would not seem to be a contributing factor.

Based on the photo of your junction box, I am wondering if it was what was originally installed by the factory, or added by the previous owner?  If you can figure out which wires control the turn signal/brake lights, maybe it would be worth disconnecting one of those at the junction box connection and see if the other side works.  Then do the same for the other wire.  I'm not sure what that will demonstrate (other than that is not where the problem lies), but it doesn't hurt to try.

I am also now thinking this is not a "ground" issue, because the source of the problem depends on whether the tow vehicle lights are "on" or "off."

QUESTION:  When you say you changed the 7-pin connector, are you referring to the receptacle on your tow vehicle, or the 7-pin plug and wiring that is connected to the trailer?  Also, have you contacted the previous owner to find out if they had the same issue, or why they replaced the 7-pin and cable (which sounds like they replaced both the plug and receptacle)?

I am following this, because I am always interested in learning about how to fix these unique electrical issues.  It may just be that you will need to take it to a shop and have an electrician trouble-shoot the problem.  Best of luck to you.

MuttonChops

Carolyn said:

This trailer has had this problem since we purchased it.
I do know that the previous owner replaced the 7pin and cable.
Yes the other trailer works fine with the TV.
We did replace the taillights with new led lights because the old ones were very dim (maybe part if the problem). We feel like it must be a ground problem but don’t know where else to look.

The extra information (above) was helpful.  Like @Bayliss find this a real head-scratcher and no longer sounds like a ground or connection quality problem. My next steps recommendation for trouble-shooting for your consideration follows.

Time for some maybe's and what ifs.
= = T@da has always had this lighting issue.
       So installing LED tail lights (wired the same) also have the problem.

Now what could be wrong.

Basic combined Stop/Turn/Running Light uses two bulbs or LED Banks (actual construction maybe different, principle is the same).
= = Running lights “On” turns on the Low Light Output bulb/bank,
= = Stop/Turn lights “On” turns on the Bright Light Output bulb/bank.

So if the Running Lights power source and the Turn/Stop power source got swapped:

= = Running Lights “On” would cause bright bulb/bank to light (full brightness) and the stop/turn when
      on would be turning on the low bulb.
      Will assume lens design and ambient light make the stop/turn nearly invisible compared to bright.

= = When the Running Lights are “Off” the Stop/Turn will energize the low light bulb/bank
       (your weak light output).

Last owner could have incorrectly wired (or perhaps correctly wired for their odd-ball TV) which was copied by you when installing the LED tail lights.

Assuming you have a 3-wire tail light assembly; running/stop/ground wires. It might be easier to try swapping wires at the tail light than the junction box. To see what happens.

11:xxPM edit to clarify basic operation text

Bayliss

Hmmmm, I believe you are on the right track, @MuttonChops.  I re-read @Carolyn's most recent post and realized that I had missed one important clue............"We did replace the taillights with new led lights because the old ones were very dim (maybe part if the problem)."  Although a dim light points to a bad ground, it does seem that this particular situation may actually be a switched-wire issue.  Your description of the "low" and "bright" output was very helpful to me for future troubleshooting, so thanks for that.

Carolyn

Thanks so much, Bayliss & MuttonChops. I really feel that you have successfully narrowed the problem down to the most likely crossed wire scenario. I have passed all of your comments to our Grandson who concurs and will work on the issue. Everyone has said it had to be a ground issue and we just could not locate a gtound problem. We replaced the taillights because the turn signals and brake lights were so very dim and while the led’s are brighter, they only masked the problem.  Thanks again and I will post results.

Carolyn

Report on solution
Bayliss and MuttonChops, you guys were right on.  My son and Grandson used your diagnosis and fixed the issue. We believe that the former owner crossed the liw bank and hign bank lights when replacing the 7 pin chord. They decided it would be an easier fix to switch wires at the taillights. They did that and all works as it should.  They feel that it would have taken them a whole lot longer to fix if the two of you had not done the excellent work.  Thanks so much for your help.

MuttonChops

Carolyn said:

Report on solution
. . . believe that the former owner crossed the low bank and high bank lights when replacing the 7 pin chord.

. . . They decided it would be an easier fix to switch wires at the taillights. They did that and all works as it should. 

Excellent News, thanks for the update.

Bayliss

Thank you, @Carolyn.  The bulk of the credit goes to @MuttonChops.  This has been a great learning experience and I greatly appreciate you following up with letting us know how you got the issue resolved.