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7 Pin Trailer plug/No voltage to 12V output to charge trailer battery

johnsills1
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johnsills1 Enthusiast

johnsills1

Posted
Posted

I have scoured the internet and even this forum and have only found one post that really addresses this issue on the 2019-2021 Silverado/Sierra 1500’s. One person here said they found the fuse that controlled it, but didn’t elaborate as to which fuse so I went and checked every fuse I saw under the hood and was unable to figure out how to fix this issue.

 

Fuse #63 says trailer power, but has nothing to do with the 12V Power Pin on the 7 Pin connection. 

 

If anyone can shed light on the solution to my problem, it would be greatly appreciated.

EddDe Enthusiast

EddDe

Posted
Posted

I pull a travel trailer so this piqued my interest. I have 2020 1500 LT with Max Trailering package. I put a 12v meter on my  truck's 7 pin connector at ground & 12v+ charging. I, too, did not get any voltage with truck off, accessory mode, or running. However, I'm pretty confident my trailer is getting at least 12v from truck when traveling. I'm guessing there must be a condition that has to be met before truck sends 12v thru 7 pin connector. Such as, trailer plug connected and 12v from trailer is detected...just a wild guess. My 30 amp fuse at #63 (Trailer battery) looks good. I'll check more when trailer is connected again.

johnsills1 Enthusiast

johnsills1

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1 hour ago, EddDe said:

I pull a travel trailer so this piqued my interest. I have 2020 1500 LT with Max Trailering package. I put a 12v meter on my  truck's 7 pin connector at ground & 12v+ charging. I, too, did not get any voltage with truck off, accessory mode, or running. However, I'm pretty confident my trailer is getting at least 12v from truck when traveling. I'm guessing there must be a condition that has to be met before truck sends 12v thru 7 pin connector. Such as, trailer plug connected and 12v from trailer is detected...just a wild guess. My 30 amp fuse at #63 (Trailer battery) looks good. I'll check more when trailer is connected again.

Thanks, I really need to figure this out. 

  • 6 months later...
Coastie Enthusiast

Coastie

Posted
Posted (edited)

Kind of an old post, but on one of my trailers the emergency breakaway system has LED lights showing the battery status, and when the truck is on, it does show the status as charging the breakaway system battery.

 

I guess you could put a meter on the trailer battery with the truck off, and see if the reading increases when you start the truck. I don't know if it is a regulated 12v to the back, or a higher (alternator) voltage for charging. 

Edited by Coastie
EddDe Enthusiast

EddDe

Posted
Posted

I hope you solved your issue by now. My fuse #63 in engine compartment for trailer battery looked fine, but still no 12v at 7-pin connector. I pulled fuse out, popped off it's cover and it is blown. Simply replacing the 30 amp fuse restored 12v at trailer connector, even when truck is off.

#63 fuse 30 amp.jpg

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