Electrical Issue – Battery Sparking & Smoking When Connected

[Travelturtles207]

Hi everyone,


We recently purchased a 2006 Jayco Jay Flight 29BHS, and we’re running into an electrical issue that we’re hoping to get some guidance on.

The Problem:​

• When we try to connect the battery, it sparks and smokes, which obviously isn’t right. I know they can a little, but it started smoking on the negative end too so we disconnected it.
• While troubleshooting, we found a larger white wire in the junction box (at the front of the trailer) that has an open ground —we’re unsure where it should go.
• The strange part is that everything was working fine when we towed it home, so we’re trying to figure out what changed. We did get a new battery because the old one wouldn't hold a charge.

What We Know So Far:​

• We reached out to Jayco and got the schematics, but they only show the wiring after the Power Center—nothing about the DC path from the battery to the Power Center or how it's routed. They didn’t have any additional guidance.
• We are replacing the junction box and starting fresh since it looks like someone previously rewired it incorrectly.

Our Questions:​

1. Could the open white wire be causing the short?
2. Why would the trailer need a ground from the truck to the trailer battery? The only white wire on the trailer cord is ground, so we’re confused about why it would be needed beyond the truck frame.
3. Is there a common failure point in the wiring between the battery, junction box, and Power Center that could explain this issue?
4. Could there be a bad ground connection somewhere in the system? If so, where would be the best places to check?
5. Could a shorted converter or other component be backfeeding power and causing the sparking/smoking?
6. Does anyone have a wiring diagram or more details on the path from the battery to the Power Center for a similar Jayco model?
7. What’s the best way to safely trace the short? Any recommended testing methods (e.g., continuity testing, disconnecting sections one at a time, etc.)?
8. Would a miswired breakaway switch or trailer plug cause this issue?

Any help or insights would be greatly appreciated! I am hoping we are on the right track.


Thanks in advance!

 

[craigav]

Pictures could be of value. It sounds as if you have a direct short which isn't all that uncommon when changing an RV battery(s) most often due to connecting a cable on the wrong terminal. Generally speaking (not always), you should have one ground wire (cable) that is white (or has a white marking on it such as white tape) and the remaining other wires are all (commonly) positive. With RV's it is common to find the black cable is the hot wire where on a boat or many cars black is the ground which causes confusion.

1. An open wire cannot cause a short (as long as it stays open of course).
2. Trailers need a good ground mostly for the trailer lights, but also for charging the battery from the tow vehicle).
3. One could say all of the wires from the trailer connector to the battery are a common failure point, generally speaking though, the failure is a loss of connectivity instead of a direct short.
4. Not likely a bad ground, other than you may have a ground wire connected to the positive battery post.
5. The converter has fuses (reverse polarity) that prevents a shorted converter (or reverse connected battery) from causing a short to continue (for longer than the time to blow the fuses, you should check them for being blown as they may be but wouldn't be the cause of the issue).
6. I don't have a wiring diagram for you, although I have looked at many, which is why if you can share a picture that may be of value.
7. The best way to trace a short is often done with a Digital Voltage Ohm Meter (DVOM). Do you have a ohm meter? Even with one, tracing a short can be a challenge.
8. Anything miswired could cause a similar issue however, chances are good that if you only replaced the battery that any miswiring would be with the work you recently did.

~CA

 

[Grumpy]

As craigav said. Only white wire or black with white tape on it would be ground. Plain black and all other colors are positive. Also...

 

[JFlightRisk]

Welcome to the Forum from Western NY State!

My first thought is the battery cables are connected backwards. Maybe what took out the old battery to begin with. There's a VERY low probability there's an internal short in the new battery. It would cause the battery to get hot to the touch. Is it a flooded lead acid type that you can check the acid level in or is it sealed? Is the trailer plugged in when you try to connect the battery? If the last battery terminal has a spark when you connect it, there's something drawing power.

 

[norty1]

It's a common error that occurs when changing out a battery w/o marking or a picture of how the old battery was wired. I made that mistake long ago and it was confusing the terminal for the white wire.

 

[Bugzilla46310]

Saw this on the Ford forum also. From the information it sounds like the problem started after you got home and changed the battery, which I am assuming is the order. If so, that in my mind would limit the problem to 3 items. 1-New battery is bad, 2-Installed new battery wrong, 3-Something shorted on the trip home. But if the original battery appeared to work correctly before you changed it at home, I feel that this would be a low probability.

 

[Mcburt]

Hi everyone,


We recently purchased a 2006 Jayco Jay Flight 29BHS, and we’re running into an electrical issue that we’re hoping to get some guidance on.

The Problem:​

• When we try to connect the battery, it sparks and smokes, which obviously isn’t right. I know they can a little, but it started smoking on the negative end too so we disconnected it.
• While troubleshooting, we found a larger white wire in the junction box (at the front of the trailer) that has an open ground —we’re unsure where it should go.
• The strange part is that everything was working fine when we towed it home, so we’re trying to figure out what changed. We did get a new battery because the old one wouldn't hold a charge.

What We Know So Far:​

• We reached out to Jayco and got the schematics, but they only show the wiring after the Power Center—nothing about the DC path from the battery to the Power Center or how it's routed. They didn’t have any additional guidance.
• We are replacing the junction box and starting fresh since it looks like someone previously rewired it incorrectly.

Our Questions:​

1. Could the open white wire be causing the short?
2. Why would the trailer need a ground from the truck to the trailer battery? The only white wire on the trailer cord is ground, so we’re confused about why it would be needed beyond the truck frame.
3. Is there a common failure point in the wiring between the battery, junction box, and Power Center that could explain this issue?
4. Could there be a bad ground connection somewhere in the system? If so, where would be the best places to check?
5. Could a shorted converter or other component be backfeeding power and causing the sparking/smoking?
6. Does anyone have a wiring diagram or more details on the path from the battery to the Power Center for a similar Jayco model?
7. What’s the best way to safely trace the short? Any recommended testing methods (e.g., continuity testing, disconnecting sections one at a time, etc.)?
8. Would a miswired breakaway switch or trailer plug cause this issue?

Any help or insights would be greatly appreciated! I am hoping we are on the right track.


Thanks in advance!

• After reading this, " The strange part is that everything was working fine when we towed it home, so we’re trying to figure out what changed. We did get a new battery because the old one wouldn't hold a charge. " I would assume that either the battery was connected wrong, or something rubbed on a positive wire and caused a short. In this case you're going to blow a fuse or breaker inside the RV. I had a short in my RV once where a cabinet screw rubbed through a positive and negative wire causing a short. I thought I was never going to find that problem because it was behind the wall. I had to go through and test every component to find the one that didn't function properly. Because you're smoking the battery terminal and not blowing breakers or fuses my guess the problem is outside the RV power center. As far as battery connections goes are the large battery wire the only wires connected to the batteries. Red on positive black on negative. The red or positive wire should go to a 30–50-amp breaker. The black to the frame. Turn the battery switch off and try to connect the wires. If it still sparks the wire are crossed. If you have more than one battery and a 12-volt system. make sure batteries are connected correctly in parallel series. Positive to positive and negative to negative. Also check that 30-50-amp breaker. Some have 30 amp my RV has a 50 amp. They are usually attached to the side of a metal box. It could be shorting out there. When you changed your battery, it may have worked loose.

 

[Mica-JAY]

Hi everyone,


We recently purchased a 2006 Jayco Jay Flight 29BHS, and we’re running into an electrical issue that we’re hoping to get some guidance on.

The Problem:​

• When we try to connect the battery, it sparks and smokes, which obviously isn’t right. I know they can a little, but it started smoking on the negative end too so we disconnected it.
• While troubleshooting, we found a larger white wire in the junction box (at the front of the trailer) that has an open ground —we’re unsure where it should go.
• The strange part is that everything was working fine when we towed it home, so we’re trying to figure out what changed. We did get a new battery because the old one wouldn't hold a charge.

What We Know So Far:​

• We reached out to Jayco and got the schematics, but they only show the wiring after the Power Center—nothing about the DC path from the battery to the Power Center or how it's routed. They didn’t have any additional guidance.
• We are replacing the junction box and starting fresh since it looks like someone previously rewired it incorrectly.

Our Questions:​

1. Could the open white wire be causing the short?
2. Why would the trailer need a ground from the truck to the trailer battery? The only white wire on the trailer cord is ground, so we’re confused about why it would be needed beyond the truck frame.
3. Is there a common failure point in the wiring between the battery, junction box, and Power Center that could explain this issue?
4. Could there be a bad ground connection somewhere in the system? If so, where would be the best places to check?
5. Could a shorted converter or other component be backfeeding power and causing the sparking/smoking?
6. Does anyone have a wiring diagram or more details on the path from the battery to the Power Center for a similar Jayco model?
7. What’s the best way to safely trace the short? Any recommended testing methods (e.g., continuity testing, disconnecting sections one at a time, etc.)?
8. Would a miswired breakaway switch or trailer plug cause this issue?

Any help or insights would be greatly appreciated! I am hoping we are on the right track.


Thanks in advance!

Did you buy it from Bish’s? They hooked my my batteries incorrectly and I almost had a fire in my brand new trailer!