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Wire Harness Problem

I had an electrical fire that damaged quite a few of the wires in my wiring harness. The car ran ok after the fire, but a lot of wires had the insulation burnt off exposing bare wire, and a number of the wires got melted together.



I have replaced most of the damaged wires by splicing in new wires, which I soldered and sealed with heat shrink.



However, I have run into a problem with four of the wires. I had four wires that appeared to be badly melted together with two of them having exposed wire a short distance from where they were all melted together. Unfortunately, I am partially colorblind and two other people who I had look at these four wires also could not see any color-coding difference between the four of them. Therefore, I could not safely just cut the bad sections out and splice in new wiring because I was not sure which wires matched up.



I carefully scraped the insulation from around the blob of melted together wires. In the center I found what appears to be a small rectangular block of solid metal. I expected to find four wires in the center with a bit of melted insulation between each wire. It appears that this group of four wires may have come this way from the factory.



Is this possible? Would there be some reason to have four wires in the wiring harness all come together in the middle of the run, and then separate back into four wires again? Any ideas on what I should do next?

It is possible that the wires were tied together at a central point. They do make common connections in the harnesses sometimes. It also may have been a connector and got fused together. Using a factory service manual for the wiring will tell you what the story is.

You probably need to find a wiring diagram for the car. Haynes or Chilton will probably do. If it is a popular car, your local library may have a manual with a wiring diagram. The color codes for wires are indicated on the diagram e.g BR is Brown B-R is Black with a Red stripe. It shouldn’t take long to figure out if the four wires are equivalent or if the colors may have shifted due to heat/age. If they are equivalent, e.g. 12 volt power from one specific fuse point, it won’t matter which you hook to which equivalent in the other half of the harness.

Wires don’t come together and, then separate again. Eight wires might come to a junction. The juction is attached to a ground, or a power source. The other wires would be from other circuits, in such circumstances.
You can identify the melted four wires if you identify the other four wires (by their colors). Get the colors, go to wiring diagrams of: Diagrams of power distribution; or: Diagrams of grounds.
Your public library IS a good place to go for such information-----Not paper manuals; but, on the library’s Web site. Go to the site ARRC (Automotive Repair Reference Center), and to alldata.com. Look up: Power Distribution, and Ground Distribution under “wiring circuits”

What model year is your beastie?

Thank you all for the suggestions so far.

to hellokit: dodge caravan 1997

I have the Haynes manual for the vehicle. I have very limited knowledge and experience reading wiring diagrams. I think it might be the sensor ground circuit. I am not at the location where the car is at the moment. I will be there in a few hours.

I do now think that all eight wires came from the factory into a single junction type box.

If this is the case, my question now is can I splice eight new wires in and then just solder them all together?

I have added a not very good picture that I took yesterday

From the photograph, that might NOT be a junction, in the middle. That might just be where the wire bundle was held together with a clamp, or band. I think that each wire on one side of the middle is a part of the same wire on the other side.
Make sure that none of the wires are touching each other. You can pierce the good area of wire, and touch the test lead of the multimeter (set on ohms) to the burned wire and establish which one is which. You could then splice in a new piece of wire from the good wire to the good section.
Still need the color of the wires in the good section in order to identify what circuits they are, and what components they serve.

What is the engine size in your 1997 Dodge Caravan?

Your photograph is probably out of focus, on the wires in question, because you held the camera too close. Back up a few inches.

caravan is 3.3 L

Unfortunately, My library did not have either database.

Car was at my brothers house. I was unable to figure out how to use his photo editing software.

Thanks to the help here, I became convinced that this was a factory junction that I was seeing. I cut eight new wires soldered all 8 together (4 to 4 with a single solder joint. I then connected the 8 wires back up to the wire harness. Car seems to be running fine.

Thanks all.

For just the reduction of aggravation, I’d take a trip to the salvage yard and look for a replacement harness. You’ll probably save your sanity and any electronic modules this harness interacts with as well.

Thank you for that suggestion.

Am I correct that it will be important to find the same year, engine size, & model, ie. 97 caravan se 3.3L with A/C etc?

Here in the greater Boston area I am guessing that it may not be easy to find.

Any idea what a used harness might cost?

I’m not familiar with the Boston area at all. Dodge made a gazillion of these vans and nearly half of them had the 3.3L, so finding one in a bone yard should be easy. The salvage yard has part interchangability charts, so let them know what it was connected to. If the part is interchangable with other years, maybe the wire harnesses are too. It’s a good start to find one. Typically, if the connectors are the same on both ends of the harness, it should be good. Take the old one with you to match these up.

Your picture seems to show black/blue wires tieing to the central point and looking at info from Autozone it shows the same color wires commoned together and tieing to pin 43 of the ECU and to various sensors, like you stated. It sounds to me you did the right thing and are fine with the repair. This may be a power wire to the sensors and not ground.

Can you tell me where on the Autozone web site you found the wiring diagram? I have been unable to find it.

After you select your vehicle then choose Vehicle Repair Guides. Then choose chassis electrical and you will see ‘wiring diagrams’ on the left side of the sceen. Click on it and then you will see the various wiring drawings to choose from. The engine is one of them.

Thank you.

All the black/light blue wires are sensor ground wires. They come together at two different places—a group of eight, and the other group of 5(?) wires. They are still common to each other. One of the black/light blue wires goes to terminal #43 sensor ground on the PCM (engine computer), and one black/light blue wire going to the Transmission Control Module terminal 51 sensor ground.
So, anyway that you want to tie all of these black/light blue stripe wires together is fine. Then, wrap electrical tape around them all.

Thank you very much. The help here has been great.

Did you ever determine what caused the electrical fire? Is it likely that the electrical fire started when you cranked the engine, i.e. engaged the starter?

Since major damage has been done to sensor ground wires, I would be concerned about a bad ground somewhere. I am thinking of a bad engine to chassis ground or engine to battery negative connection. Something that drew a lot of current tried to reach the negative battery post through the sensor ground wires. You might be proactive and clean up the ground connections to the battery, engine, and chassis.

Did you have to ask the embarrassing question? (smile)

I forgot to disconnect the battery when replacing the starter motor. Dumb dumb dumb! I knew it needed to be done.