2670MK with 12 volts on the frame

[JeffnDeb]

De-winterizing the trailer. When putting the batteries back in, the ground wire off the battery slipped and hit the frame, where it sparked. Thinking that was strange, I got of the DVM and found that I have 12 volts between the battery negative and the frame?? I'm thinking this can't be right. The 7 pin doesn't seem to have any issues when connected between the truck and trailer. Also, the display in the trailer shows full charge on the batteries. I would have never known this because all looks good, except for when it sparked. No blown fuses, so I'm kind of thinking this might be normal??? Thx for any info.

***Update***
Took the trailer into town today to repack the wheel bearings. I got to looking at the truck connected to the trailer and thought that there was no way that +12V could be on the frame. I grabbed a different DVM and the frame now showed that it was grounded. I rechecked with my original DVM and it was still grounded. Not sure what happened last night to show a voltage potential on the frame. Now everything looks as it should.

Thanks for the inputs.

 

[Chewwi]

De-winterizing the trailer. When putting the batteries back in, the ground wire off the battery slipped and hit the frame, where it sparked. Thinking that was strange, I got of the DVM and found that I have 12 volts between the battery negative and the frame?? I'm thinking this can't be right. The 7 pin doesn't seem to have any issues when connected between the truck and trailer. Also, the display in the trailer shows full charge on the batteries. I would have never known this because all looks good, except for when it sparked. No blown fuses, so I'm kind of thinking this might be normal??? Thx for any info.

Was the battery ground wire (negative cable) that sparked also connected to the battery negative terminal?

2020 2600RB,
2017 Silverado Crew Cab 1500, 6.2L

 

[OurNewEra]

De-winterizing the trailer. When putting the batteries back in, the ground wire off the battery slipped and hit the frame, where it sparked. Thinking that was strange, I got of the DVM and found that I have 12 volts between the battery negative and the frame?? I'm thinking this can't be right. The 7 pin doesn't seem to have any issues when connected between the truck and trailer. Also, the display in the trailer shows full charge on the batteries. I would have never known this because all looks good, except for when it sparked. No blown fuses, so I'm kind of thinking this might be normal??? Thx for any info.

I don't think 12v + on the frame would be normal. Especially when it serves as ground for the 12v system. Was your trailer plugged into shore power when you found this condition? If so, it might be something wired incorrectly with the converter. I know there are members more knowledgeable in RV electrical systems than myself.

 

[JeffnDeb]

Yes, it was connected. I could see a little spark due to completing a circuit. But, it was much more than that. And when I measured 12 volts on the frame, that doesn't seem right. In the US, the norm is usually to have your frame grounded.

 

[JeffnDeb]

Nope, we were not connected to shore power, was stand alone.

 

[triplethreat]

In your first post....you say "batteries".....so do you have more than one battery or was that just a slip of the tongue? Secondly....if you have more than one battery, was the other battery's neg post cable already connected to the battery?

 

[llr2800]

If the positive terminal was connected and the negative not the 12V from negative terminal to frame is normal

And the spark would be from the load of any connected 12v items. No if the spark was more like arc welding and you have 2 batteries I suspect the other positive is connected to the frame