Wires on passenger side battery slowly melting and high battery temp when idling at a stop(135)

[Aiden_400ex]

I have a 2004 ram 2500 5.9 cummins and I noticed while sitting in a drive through my battery temperature was 135 degrees, after I got back on the road and was crazing at about 40 the temp went back down to the low 80's, outside air temp was about 60 degrees, got home and checked the driver side battery and it was fine but the passenger side wires looked like thisthe truck starts and drives completely fine but battery temp rises when idling after the truck is warmed up. I know the red wire is from my alternator, but not sure about the 2 black wires, what is causing them to get so hot? Thanks.

 

[MikeT]

Only one thing will cause a wire to overheat and melt it's insulation high current. When the truck is idling something is causing excess current to be drawn from the right side battery. Figure out where the melted negative wire goes and that will most likely be the cause of the high current drain. The fact that only one of the negative wires melted insulation is your best clue to the culprit.

Mike

 

[Aiden_400ex]

The black wires that are melted are on the positive terminal, and both of the black wires are melting the top one is just melted to the plastic around it, and the red is straight from the alternator and the black go down to the thing on the right side of the rusted bolt, I'm taking it to a shop this Tuesday so I'll ask them about it, thanks for the reply.

 

[MikeT]

As far as I know ALL Chrysler vehicles (my knowledge starts at about 1950) are negative ground. Ground wires on my 2006 2500 (CTD) are black, positive wires are red. If you have black wires on the positive side of that battery and they go to ground and red wires on the negative side of the battery and they go to the alternator or regulator, then I'm very surprised that the battery in question has not exploded. Has that battery been changed recently or has any electrical work been done on the vehicle recently? Something seems mighty strange to me and I can hardly believe that this vehicle is still running. The two batteries in my truck are wired in parallel, plus to plus negative to negative (red to red and black to black). Red is positive and black is negative. The parallel wiring of the batteries essentially gives double the starting current of a single battery setup. same 12 volts but twice the cranking amps.

Mike

 

[RamDiver]

As far as I know ALL Chrysler vehicles (my knowledge starts at about 1950) are negative ground. Ground wires on my 2006 2500 (CTD) are black, positive wires are red. If you have black wires on the positive side of that battery and they go to ground and red wires on the negative side of the battery and they go to the alternator or regulator, then I'm very surprised that the battery in question has not exploded. Has that battery been changed recently or has any electrical work been done on the vehicle recently? Something seems mighty strange to me and I can hardly believe that this vehicle is still running. The two batteries in my truck are wired in parallel, plus to plus negative to negative (red to red and black to black). Red is positive and black is negative. The parallel wiring of the batteries essentially gives double the starting current of a single battery setup. same 12 volts but twice the cranking amps.

Mike

In the first picture, we can see the large black wire is connected to the '-' post but it looks like someone has added aftermarket wiring for something with both the red and black smaller gauge wires wires connected to the positive post.

Also notice, the OP is directing us to the melted BLACK wires on the positive post.

What would you bet that the pair of black smaller gauge wires belong on the negative post?

.

 

[Daw14]

Some fresh terminals will not hurt the situation, they may help in the long run. Need to determine what the two wires on the hot are actually going to operate.

 

[turkeybird56]

In the first picture, we can see the large black wire is connected to the '-' post but it looks like someone has added aftermarket wiring for something with both the red and black smaller gauge wires wires connected to the positive post.

Also notice, the OP is directing us to the melted BLACK wires on the positive post.

What would you bet that the pair of black smaller gauge wires belong on the negative post?

.

Something is definitely not wired right, and/or the alternator is putting out way too much current, all IMHO.

 

[RamDiver]

I recall in my youth, wiring up odds and ends directly to the battery and sometimes we didn't have nice new red and black wire but at the least, we would apply several wraps of red electrical tape to transform a black wire into red.

Otherwise, you're just heading for grief not following the standard convention of red (+) & black (-) and that's not just an OCD thing.

.

 

[Aiden_400ex]

I inherited the truck from my uncle after he unfortunately passed away in August, and the 2 black wires have always been on the positive if I remember right, but I can't remember if they've always been melted or not, I did replace the batterys in september, I had an aftermarket alarm system removed in February so maybe the guy that did it could have put something in the wrong spot, there was also a fuse that was melted coming off of the driver side battery that I also have no clue what it goes to. I am not home till tomarow so i will post a pic of the fuse and where it goes.I won't be driving it until I take it to the shop. I think my alternator is okay cause my battery voltage has been exactly where it's supposed to be around 12.6-12.7 while driving. Thanks for the replys I will post an update on what the shop says about it.

 

[Aiden_400ex]

In the first picture, we can see the large black wire is connected to the '-' post but it looks like someone has added aftermarket wiring for something with both the red and black smaller gauge wires wires connected to the positive post.

Also notice, the OP is directing us to the melted BLACK wires on the positive post.

What would you bet that the pair of black smaller gauge wires belong on the negative post?

.

I was think that but the whole time that I've had the truck there always been on the positive post, and it was my uncles daily driver before and I drive it home almost 250 miles so I would think that somthing would have happened before.

 

[RamDiver]

I was think that but the whole time that I've had the truck there always been on the positive post, and it was my uncles daily driver before and I drive it home almost 250 miles so I would think that somthing would have happened before.

I learned long ago, just because something was built a certain way or "it's always been that way" does not make it correct. You identified the black wires as melting, I'm suggesting you investigate what they're connected to and why they are too hot.

Absolutely do not connect the melting smaller black wires to the negative terminal before you trace them to their destination and prove where they should be connected first.

If the black wires are getting warm enough to melt, I'd disconnect and insulate them before I'd allow them to continue cooking.

Either they are connected wrong or they are connected to a failing device that is not fused properly. The correct fuse value would open long before the insulation melts, that's what fuses are designed and used for.


Update;

If the task of tracing the two smaller black wires is too much of a PITA, try tracing the two smaller red wires on the battery instead. When you finally identify what is connected to the smaller red wires, the device will also be tied to a ground block OR... you may find the two small black wires.

I have no way to know if that is how your wiring is connected but I do know for a fact that no conductor should ever be allowed to get hot enough to melt the insulation. You're risking damage to the connected device and/or the wiring in your truck.

If these black wires are co-located with any other wiring, now that other wiring is a risk of being damaged and requiring replacement.

.

 

[tron67j]

You have the general answer, either too much current flowing through the wires, or poor connections, maybe a combo from the pictures appears to be your problem. Looks like some aftermarket wiring add one, maybe to fog lights or some other device? Get back to basic wiring and connect any device properly through a switch in a dedicated fuse.

 

[Dean2]

I was think that but the whole time that I've had the truck there always been on the positive post, and it was my uncles daily driver before and I drive it home almost 250 miles so I would think that somthing would have happened before.

You put in new batteries, you had someone remove an aftermarket alarm, you think but aren't positive it was always wired this way, and there is more melted stuff to cut out, but it can't be any of the things suggested. Will be interested to hear what you find when you get it into the shop.

 

[chri5k]

The black wires that are melted are on the positive terminal, and both of the black wires are melting the top one is just melted to the plastic around it, and the red is straight from the alternator and the black go down to the thing on the right side of the rusted bolt, I'm taking it to a shop this Tuesday so I'll ask them about it, thanks for the reply.

This probably another clue. How many other electrical connections like grounds have rusted bolts? A bad ground or two will cause more current to go through the other grounds. Also, bad connections raise resistance and cause heating. A thorough check / cleaning of all grounds and high current circuit connections would be my first step.

 

[[email protected]]

Looking at the black wire I see that the crimped terminal obviously got very hot. The red wires obviously got very hot as well. When a crimped terminal gets very hot, it is typically because the crimp is not very good and the terminal offers high resistance. Being as the red wires are also overheated, I’m assuming someone installed an accessory and it was wired with wires which are not large enough to handle the current requirement of the accessory. It’s possible too small wiring was used.

 

[Dusty]

In a low voltage, high current circuit, the threshold from pure conductive to resistive is very, very low. In a 20 ampere circuit, adding just a couple of ohms resistance at a terminal point can cause heating. The heating in most automotive circuit situations is usually nearest a connector or termination point.

From the pictures you supplied, I would suggest cleaning/redressing all the connection points, including the battery terminals.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build Date: 3 June 2018. Now at 88148 miles.

 

[RamDiver]

From the pictures you supplied, I would suggest cleaning/redressing all the connection points, including the battery terminals.

While you're at it, use a battery post/clamp cleaner as shown below. And, apply a thin film of dielectric grease to both the battery posts and clamps.



.

 

[inuyasha-rules]

The second photo looks like a heat shrink butt splice to me. Maybe it was shrunk using a torch and caused damage to another wire...

 

[Dean2]

So Aiden, what was the upshot on the melted wires?

 

[Aiden_400ex]

I just got the truck back from the shop today, it turned to be a bad alternator(was constantly pumping out 15.5V) and the smaller gauge wiring just couldn't handle it, and the intake air heater relay blew as a result of the high amps. The shop replaced all the melted wiring with bigger gauge wiring and replaced the alternator and the intake air heater relay's. I will post comparison pictures in a hour or two when I get home, thanks for all the replies everyone.