Factory Trailer Wiring problem

[tahoety]

Anyone got any ideas....

I've been to 3 different trailer places to get this issue resolved. When testing the 7pin factory trailer plug.

Right blinker works ok.
Left blinker blinks both left and right trailer light.
Brakes turn on only left trailer light.

Everything light wise on the Tahoe works fine. Trailer places are telling me its a factory module issue. Chevy is telling me they have no clue what to do.

Anyone ever run into this?

Thanks,

Ty

 

[duketter]

Maybe you tried this already but did you check the fuses under the hood by the engine? Not the fuses inside the cab. I was having these problems on my trailer lights until I figured out there are actual separate fuses under the hood that are specifically for your trailer lights only. I had to replace 3 of them to get my trailer lights to work properly and now they work perfect. Just a thought if you haven't look there.

 

[Pebo]

2012 trailer wiring issue

I have a 2012 Tahoe with the factory towing package. Today I bought a trailer with electric brakes and believe the 12V wire doesn't have power. I have looked online and see that on the 7 pin adapter, as you look at it on the vehicle, the top right tab should be a 12v always hot line that charges the brake battery and powers the 12V lights. Unfortunately, my lights and battery aren't working/charging, so checking using a test light and while the vehicle is running, the light does not light up (the light works on other power sources). I've looked for a fuse for this circut and haven't been able to find it.

To clarify, I test lighted from a "GOOD" ground to the the top right tab and the light does not come on. Am I checking this circut correctly? I've looked under the hood and also inside the cab on the driverside dash board for the correct fuse but no luck. Any idea where the fuse is and what number it may be?

Thanks!

 

[amtronic1]

Sounds like your left blinker wire and your brake light wire are switched.

 

[Pebo]

I have a 2012 Tahoe with the factory towing package. Today I bought a trailer with electric brakes and believe the 12V wire doesn't have power. I have looked online and see that on the 7 pin adapter, as you look at it on the vehicle, the top right tab should be a 12v always hot line that charges the brake battery and powers the 12V lights. Unfortunately, my lights and battery aren't working/charging, so checking using a test light and while the vehicle is running, the light does not light up (the light works on other power sources). I've looked for a fuse for this circut and haven't been able to find it.

To clarify, I test lighted from a "GOOD" ground to the the top right tab and the light does not come on. Am I checking this circut correctly? I've looked under the hood and also inside the cab on the driverside dash board for the correct fuse but no luck. Any idea where the fuse is and what number it may be?

Thanks!

UPDATE: my interior 12v lighting inside the trailer don't work and in addition the trailer brake battery doesn't seem to be charging. Trailer brake, tail and clearance lights along with the blinkers seem to be working okay.

 

[rockenthebowtie]

If your talking about terminal E on the connector it would be in the under hood fuse block 40amp fuse stud 1 fuse#68

 

[Pebo]

If your talking about terminal E on the connector it would be in the under hood fuse block 40amp fuse stud 1 fuse#68

Yes, that is the correct one, thanks, but unfortunately I still don't have power to the 12v accessory pin. I checked the voltage between the the two fuse tabs and no village there either.when I pulled the fuse,I noticed the left tab, the tab near the out side if the fuse box was loose and connected to a bolt outside of the box. Right next to this bolt is another bolt with a red power wire. I'm wondering is there supposed to be a jumper between these two books?

 

[rockenthebowtie]

No it doesnt need to be jumped the rigjt and left trailer stop lamps are on the same circuit intergrated with printed circuit board relays in the fuse block assy and you say those work..chances are you may have a bad fuse block

 

[Pebo]

Sorry for my last post, I did it from my phone and obviously, it just didn't come across exactly as I had hoped.

Anyhow, I went to my dealer and they immediately knew what the problem was. The tech reached in near the steering column and unwrapped another red/hot wire and attached it to the stud bolt that the 40 amp #68 fuse was attached to. Now I have power to the 12 v accessory pin on the trailer connector.

In the attached picture, arrow #1 is the 40 amp fuse, mentioned above. Arrow #2 is stud #1 that had no wire attached but that the tech added the power wire to.

I can't believe that Chevy would not connect all the wiring on a truck with the factory towing package, go figure?

Hopefully, if anyone else has this problem that this helps.

 

[samotahoe]

PEBO! I used to install these wirings when I worked at uhaul. the reason your 12v supply isn't working is because its not hooked up, when I would install a trailer brake system on the chevy's you have to find the wires that are taped beside the loom by the fuse box and hook them up accordingly to the battery, preferably with a relay or fusable link...... oops just saw your update..... lol yes the reason chevy didn't hook them up all the way is because not everyone uses it and they don't want everyone having issues (electrical wise). but in any case glad you figured it out.

 

[samotahoe]

tahoety: to answer your question, you might have a wire that was pinched underneath and is touching another wire for the other turn signal, its a pretty simple set up you just need to unloom your harness underneath near the frame and trace.

 

[tahoedude771]

Hey guys, try looking at this trailer wiring guide - it may help.

http://www.hitchanything.com/trailer-wiring-diagram-guide.html

Good luck!

 

[Bolt]

Trailer wiring

I have a 2004 Tahoe. All the truck signals work fine, but when I test the 7pin factory trailer plug:

The right blinker works ok.
The left blinker blinks both left and right trailer light.
The brakes turn on only left trailer light.

Anyone know what the problem is?

Thanks,

Drew