Trailer 7 pin no power to parking lights

[ShamrockShooter]

 

700 miles on my travel trailer no issues. I go to hook up to leave campground yesterday and the trailer app light test said issue found with running lights, and my trailer running lights only don't work.

 

The trailer running lights work just fine on my father's 16 Silverado so I know it's not the trailer.

 

Checked fuses on my truck they look good. Thinking trailer control module? Not getting a 12v signal on the 7 pin other than the open positive prong. Not sure if those are powered unless there is something plugged in.

 

Anyone else have this issue?

 

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[davester]

maybe test that power is on both sides of the fuse?  If it's not that, and you want to figure it out/fix it yourself, spend the money to get a subscription to the full-service manual for your truck.  It'll have the wiring diagram for your truck, and then start from the power source for the trailer plug, make sure it's got power, then go to the next connector for that wire and test that it's still got power, and repeat until you stop getting power.  Then figure out why not.

 

The FSM should also have a diagnostic procedure for why it's not working as well, but may require the use of a computer as part of the process.

Edited August 6, 2019 by davester

[ShamrockShooter]

maybe test that power is on both sides of the fuse?  If it's not that, and you want to figure it out/fix it yourself, spend the money to get a subscription to the full-service manual for your truck.  It'll have the wiring diagram for your truck, and then start from the power source for the trailer plug, make sure it's got power, then go to the next connector for that wire and test that it's still got power, and repeat until you stop getting power.  Then figure out why not.
 
The FSM should also have a diagnostic procedure for why it's not working as well, but may require the use of a computer as part of the process.

Thanks for the suggestions. If this was an older truck out of warranty I would be all over it, but I happen to be bringing my truck in soon to the dealer so I will mention it to them. If anyone else had this problem I thought it would give me a head start to point them in the right direction.

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[Rsktm300xcw]

Tell the dealer there is a bulletin for the trailer light control module reprogram. The truck is very sensitive to how much load is on each circuit. Too low or too high and it shuts the circuit down. I needed to change my running lights to led to reduce the amperage this got the running lights working however when I did I also swapped the tail / brake lights to led which reduced the load too much so they wouldn't work. I needed yo add resistors to fix that. The reprogram of the trailer light control module reduces the sensitivity to help with this. There are some extensive posts about this. I believe that you can find them under cold weather electrical problems. People originally thought the problems were temperature related.

[ShamrockShooter]

So I hooked the 19 loaner up to my trailer and all the trailer lights worked just fine. Dealer said they tested my truck and had 12v coming from all the 7 pin connectors. Not sure what is going on. I saw the other posts about the reprogram of the trailer control module. The only thing is I towed this trailer 700 miles with no issues. I would think if it was an issue with the draw of my trailer lights, the issue would have appeared right away not after 700 miles. They said they are going to look at it again on Monday.

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[Rsktm300xcw]

Get the reprogram done. It will probably fix most of the problems. I pulled out most of my hair fighting with this. I am an electrician by trade and spent about 3 weeks and 30 or so hours going over every last wire on my trailer and found no problems. Changing out the lamps and the reprogram seems to have solved the problem. Not worth fighting with it until the reprogram is done. Then you can change the lamps and or add resistors to get the loads right so the app sees enough draw to know the lamps are working but not too much draw so it turns them off.

[Rsktm300xcw]

There is a lot of info on this in previous posts on pages 9 and 11, also a thread on April 8th. Check those out.

[Rsktm300xcw]

 

[ShamrockShooter]

Well I didn't get the details but the advisor said the tech fixed the problem. Truck isn't done yet so have not seen the repair order. I'm guessing they did the update

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[Rsktm300xcw]

Good luck!

[Steve-2019]

13 hours ago, ShamrockShooter said:

Well I didn't get the details but the advisor said the tech fixed the problem. Truck isn't done yet so have not seen the repair order. I'm guessing they did the update

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Let us know what the repair order says. please.

[ShamrockShooter]

From memory the repair order said they found a loose connection and replaced the whole 7 pin assembly. Hopefully this weekend I can hook it up to my trailer and test it out.

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[Jack D]

I am not having a lighting issue, but my trailer test tells me that the electric brakes are not connected. About 30 seconds later, I get the message that my saved brake settings are enabled. My trailer brakes work just fine, and the gain settings  adjust the brakes normally, so no problems with trailer brake operation. Don't know why the test says that the brakes are not connected???

[davester]

The resistance is slightly wrong?  Or not all the brakes are working?

[ShamrockShooter]

From memory the repair order said they found a loose connection and replaced the whole 7 pin assembly. Hopefully this weekend I can hook it up to my trailer and test it out.

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Hooked up the camper an now my parking lights work. Hopefully they stay on this time now that they replaced the recepticle

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