Confusing turn and brake light problem

[mikeandnora]

We hooked up yesterday to come to springstream and much to my dismay the lights do not work right. We ended up coming up anyway, but only by confusing drivers behind us the whole way.

Tow vehicle is an 04 Yukon denali with factory installed tow package and 7 way.

Brake light indications seen on airstream:
Brake- only left lights come on.
Left turn sig- left turn lights operate correctly.
Right turn- both left and right lights flash.
Hazard lights- lights flash like they should
Running lights- lights illuminated like they should be.

I replaced all bulbs. No change.
I checked all fuses
I checked wiring from 7 way and it is fine all the way until it goes into the frame and out of sight.

I pulled out the multimeter to test the seven way and:
All connections read like they should except that the right brake/turn is a constant 12v.

What really throws me for a loop is the fact that the right lights are not constantly illuminated.

Any thoughts?

[Wingeezer]

Without tracing out all the wiring, I can't quite get my head around it to see if my comment makes sense or not, but my first reaction is if the lights worked ok before, then I would suggest checking all your ground connections, bad grounds can sometimes make weird things happen with signal lighting systems.

Just a thought ......... Brian

[Jammer]

The problem you describe is caused by a bad ground for the right tail light assembly.

If you clean and tighten the ground connections the problem should clear up. I make use of stainless steel toothed lockwashers for ground connections as they improve the reliability considerably.

[Splitrock]

I think it's a ground issue too. The way I'd test it is to make a new ground with a jumper wire to the frame and test the socket with a jumper light connected to the grounded test wire. If it works, the ground was the issue. Of course you could just reattach the ground and see if it works. I like to diagnose before I start changing stuff because sometimes my repairs add a problem that wasn't there in the original equation:-)

I have 4 trailers using the 7-ways on my two tow vehicles. My light test kit never really cools off.

[mikeandnora]

Are you guys referring to the vehicle or airstream grounds?

Thank for all the help!

[Splitrock]

Trailer ground. I don't work on the trailer with the tow vehicle plugged in. Trailer problems too often become TV problems. I test with my battery charger and when it's all good, I plug in the TV to try it.

I understand some people like to blow fuses in their TV . . . I'm not in that crowd:-)

[Jammer]

It would be the ground connection for the right rear taillight assembly on the 'stream. I don't know quite how it is on an Excella but I believe you remove the tail light lens first and then remove the lampholder and reflector assembly, and the ground connection is under that.

[mikeandnora]

Thanks. I will clean them all tomorrow.

[Wsmith]

Originally Posted by fishandfly

We hooked up yesterday to come to springstream and much to my dismay the lights do not work right. We ended up coming up anyway, but only by confusing drivers behind us the whole way.

Tow vehicle is an 04 Yukon denali with factory installed tow package and 7 way.

Brake light indications seen on airstream:
Brake- only left lights come on.
Left turn sig- left turn lights operate correctly.
Right turn- both left and right lights flash.
Hazard lights- lights flash like they should
Running lights- lights illuminated like they should be.

I replaced all bulbs. No change.
I checked all fuses
I checked wiring from 7 way and it is fine all the way until it goes into the frame and out of sight.

I pulled out the multimeter to test the seven way and:
All connections read like they should except that the right brake/turn is a constant 12v.

What really throws me for a loop is the fact that the right lights are not constantly illuminated.

Any thoughts?

A loose ground will not send the signal on different wire paths it would only cause the light not to work but usually the ball connection with ground it anyway.


1986 trailer manual shows the following code for the trailer
Red- Stop/left turn should go to yellow on TV
Green- Taillight/ Clearance should go to brown on TV
Brown- Stop / right turn should go to green on TV
Yellow- Backup Should go to purple on TV
White- Ground same
Blue- Brake same
Black- 12V Positive should go to Red/black on TV
If you can't get into the TV to see what pens the wires are on then you will have to use a light pen or a volt meter.

I think you have two of the wires you listed crossed. The brake is activating the left turn signal. I think you can swap the red and brown wires on the trailer connector and fix it. Trailer Wiring Diagrams | etrailer.com You can go down to the seven pin connector pair and substitute the airstream color code to the wire destination and it will give you the correct pen number on the plug and location
If I am reading the data right you have the brake from the TV and the Right turn signal wires reversed.

HOPE I AM STILL THINKING STRAIGHT AT 1:30AM

First you said right turn both right and left flashed.. then when you used a meter said the signal was constant?

[mikeandnora]

The wires listed in the manual match up to the factory tv 7way. I went through them all again today and am beginning to think the problem lies in the tv flashed relay. I have found some threads that indicate it is the cause of many other turn signal issues although I could not find anyone that has had my exact issue set.

The right turn stop in the 7 pin does show constant 12v, without brakes or anything else like parking lights on. Once turn signals are used it will go off the constant 12v to flash. I still do not
Know why the 12v doesn't result in the right light being on constantly but oh well. I will try and have another tv test out the trailer lights tomorrow.

Thanks again for all the help.

[Wsmith]

I posted under the assumption that you had a new TV or Kid Prank or something similar.. I once had someone swap a few plug wires. I see this has happened on a known working situation. Hook another TV to the trailer if you have one available. This will tell you the trailer is right.

Good luck with it.

If things work correctly on TV not hooked to the trailer. Wonder if the additional draw from the trailer is causing the problem on a weak component.

[Wsmith]

Oops was telling you what you had already stated. I got distracted and skipped reading your second paragraph before posting a reply.

[mikeandnora]

I really appreciate the help. I made it all the way home without incident or moving violation so all is well. Happy airstreaming!

[mikeandnora]

In case there is anyone out there with a chevy product having this type of issue, it was actually the turn signal controller. Behind the fuse panel at the drivers door there is a 10 pin ( my guess at number of pins) signal switch that completely controls your trailer lights. It is about $70 from an auto parts store (saw it for $40 online as well)

Order part, remove trim beneath steering wheel to gain access to back of fuse panel. Disconnect battery. Pull big rectangular signal controller out and put in replacement. Reconnect battery and test trailer lights. Put panel back on.

FYI. The thing you are replacing is also the module that makes the click/clack in the dash when your turn signal is on.

Final note. I found this info mentioned in random chevy and gmc forums. None of the problems I read about were exactly what I had, so I would suggest that if you have anything weird about your signals it may be this.