Technical alternator cable wire

[dannylee]

Hey guys

so my battery light came on my twin air 2018 500. i checked the alt voltages which pointed to the alternator issues. when i removed the alt i noticed this cable was broken away from the alt. any tips on how to repair this cable ?

appreciate any input, thank

 

[Leroypanda]

Can you not crimp a new connector on there?

 

[chris3234]

Get a plug a section of wiring from a scrap yard and splauce the connector to the damaged one on your car would get my vote

 

[dannylee]

thanks for the comments, i went to fiat today and they couldn't help me with a new connector but i got the new internal pin so i've set those together and now will splice it back onto the car. I was a bit stressed when i saw it so my logical brain didn't kick in until later today, i thought felt sure it was the alternator until i saw this wire so it threw me off a little.. But thanks, I appreciate your input.

 

[John202020]

Any bets that's the field coil supply?

 

[chris3234]

Any bets that's the field coil supply?

Allmost certainly

Too small for anything else

All-through could be the control if its a smart alternator however

 

[dannylee]

Any bets that's the field coil supply?

Thats what i landed on. I just hope that's the issue, everything pointed to the issue being the alternator (11von battery when running, battery light on, lost power steering) but when I saw this it looked like a smoking gun. My questions are though, how would the field coil supply error manifest itself ? and how did it become broken in the first place, I didn't notice any signs of corrosion, although it is a small wire, did i damage it under disassembly ? i didn't think i was being too aggressive with it on removal. The car is 2018 with only 46000km, which is early to have this type of fault imo. I've re-plugged the cable now and sent the alternator for a check while its out.

 

[GettinBetter]

Its not a field coil supply. Its the LIN cable and is a digital signal from the ECU to tell the Inteligent alternator when and how much to charge. It relies on the digital signal from the neg battery terminal to decide how much the battery needs.

 

[GettinBetter]

I managed to dislodge mine whilst disconnecting, but didnt break the wire. Its a real bugger to get it back onto the other part. Least I didnt think I'd broken it, although I may have damaged it as mine isn't charging again.

 

[dannylee]

Its not a field coil supply. Its the LIN cable and is a digital signal from the ECU to tell the Inteligent alternator when and how much to charge. It relies on the digital signal from the neg battery terminal to decide how much the battery needs.

thanks so much for that extra detail, for the life of me i cannot understand why it would be broken though, its been haunting me that i damaged it during disassembly but i wasn't heavy handed and i didnt feel it break, i had the alternator tested today (he couldnt test the LIN cable input though) i'll be putting it back on the car tomorrow so i really hope that fixed the issue

 

[dannylee]

I managed to dislodge mine whilst disconnecting, but didnt break the wire. Its a real bugger to get it back onto the other part. Least I didnt think I'd broken it, although I may have damaged it as mine isn't charging again.

i performed a field repair i removed the pin from the connector and replaced it with a long splice, then i could work on it off the car. i cant believe how much work a alternator removal could be, i remember changing a alternator at the side of the road in my old polo

 

[GettinBetter]

Its difficult to test when disconnected as they perform a handshake procedure to ensure they are both the correct components. But if you slide a pin down the side of the connector and connect to an oscilloscope, you can clearly see the square wave comms.

 

[dannylee]

Well I got the alternator back from the test place. He said he couldn’t test the LIN portion of the alternator but he said the rest was working fine. I put it back on the car, connected it up and….:nothing well 11.8v to be exact. Exactly the same. So now I’m going to source a new alternator. I did put the multimeter on the alt itself but I got 0 v onto the alt body

 

[GettinBetter]

I replaced the Intelligent negative battery terminal, and it worked for quite a while. The neg battery terminal was about 20 quid on fleabay, secondhand.

Although to be honest, I had already replaced my alternator and it didn't make any difference. I just thought I'd mention it in case you wanted to replace the cheaper part first?

Currently mine must be like owning an electric car as I have to charge it every two days, but I alternate it with taking the motorbike, plus I only work three days a week. I just can't be assed to sort it yet as I have a much more interesting project on the go.

 

[GettinBetter]

Here's mine, and looking at it now zoomed in, it looks like I may have stressed it where it comes out of the socket, so the wires internally may be broken. It lasted for 99% of my recent trip, which was about a years worth of vibration.

 

[GettinBetter]

...and here's the sort of wave, on that LIN wire you should expect when it is working.

 

[dannylee]

View attachment 451266

...and here's the sort of wave, on that LIN wire you should expect when it is working.

Thanks, i dont have that tool so im struggling there. A quick question if you don’t mind. To check the continuity of the cable, I’m assuming it’s from the LIN to the intelligent negative on the battery post ? Just want to make sure that there isn’t a cable break I can’t see

 

[GettinBetter]

Thanks, i dont have that tool so im struggling there. A quick question if you don’t mind. To check the continuity of the cable, I’m assuming it’s from the LIN to the intelligent negative on the battery post ? Just want to make sure that there isn’t a cable break I can’t see

No, and don't quote me on this.
But the colours of the wires at the negative terminal are different, therefore I assume they go to the engine ecu or the body ecu. I replaced the neg terminal post at that point, so never dug any further.

 

[The Panda Nut]

thanks so much for that extra detail, for the life of me i cannot understand why it would be broken though, its been haunting me that i damaged it during disassembly but i wasn't heavy handed and i didnt feel it break, i had the alternator tested today (he couldnt test the LIN cable input though) i'll be putting it back on the car tomorrow so i really hope that fixed the issue

Smme Fiat parts are, how shall I put it politely.. delicate! Very easy to break some bits and not alwasy easy to see how they should be unclipped.

 

[dannylee]

No, and don't quote me on this.
But the colours of the wires at the negative terminal are different, therefore I assume they go to the engine ecu or the body ecu. I replaced the neg terminal post at that point, so never dug any further.

Thanks so much again for your input .