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Electrical help - wires in battery compartment

dassaur

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So I have been meaning to tackle this issue for a while and got some time today. I have been running DTC B1517 5A (battery voltage plausibility) for who knows how long. I have noticed no symptoms except the existence of the code. For context I acquired the car in Feb 2020. The battery is definitely good, it's a year old and for completeness I got it tested a few weeks ago and also fully charged it overnight.

The first thing I did was check every BCM fuse in all fuse boxes and they were all good.
I hooked up the scan tool and the voltage at the battery posts themselves, under the hood and via the scan tool were all reading identically.
I then thought to take the battery out and have a ferret around. I removed the entire battery cradle assembly and there was a slight bit of corrosion on the battery cradle. Cleaned and resprayed all good. There were no loose cables, fusible links were all good and all grounds looked fine after a visual inspection and checking for tightness.

I then noticed a loose wire which looks like it has been broken off a c-clip type terminal on the negative battery side. Picture below:
IMG_20210801_164548058.jpg


So I fixed it all up, put the scan tool back on and oh boy. DTCs left right and centre - EXCEPT the original DTC!!!
B147E 04 Battery Saver Relay Set Secondary Circuit Open
B3811 01 Rear Washer Relay Circuit Short to Battery
B3811 04 Rear Washer Relay Circuit Open
B3873 01 Front Washer Relay Circuit Short to Battery
B3873 04 Front Washer Relay Circuit Open
B3883 01 License Plate Lamp Circuit Short to Battery
B3883 04 License Plate Lamp Circuit Open
B1325 03 Control Module Power Circuit Low Voltage

And for some reason, I can't open the liftgate either via the traditional method.

I ran out of light so tomorrow's job is to remove that ground and see what happens. But in the interim I thought I'd ask if anyone had any ideas.
Can anyone check their car to see what's going on with the cable. It's the one with the insulation around it as per below pic.
IMG_20210801_164610861.jpg

It looks potentially related to tow wiring but can't be sure. While we're at it, that taped up connector - anyone else got it?

Thanks !!!
 

Skylarking

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On my Motorsport Edition, I have the very same unused and taped up connector as you do and I have a dealer fitted towbar ;) So not sure what feature the blue and purple/white wires provides :rolleyes: From looking at the Service Manual page 8892, I suspect it's the trailer brake harness connector which in my case I don't use since I don't have a trailer brake controller :p

As to the foam covered cable connected to the battery negative via a bolt eyelet, well I also have the very same but in my case it ain't brocken :cool: I haven't tried to trace what this cable is for by looking at the cumbersome Service manual :rolleyes:

Why you get so many errors when fixing the brocken wire, I've no idea...
 
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dassaur

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On my Motorsport Edition, I have the very same unused and taped up connector as you do and I have a dealer fitted towbar ;) So not sure what feature the blue and purple/white wires provides :rolleyes: From looking at the Service Manual page 8892, I suspect it's the trailer brake harness connector which in my case I don't use since I don't have a trailer brake controller :p

As to the foam covered cable connected to the battery negative via a bolt eyelet, well I also have the very same but in my case it ain't brocken :cool: I haven't tried to trace what this cable is for by looking at the cumbersome Service manual :rolleyes:

Why you get so many errors when fixing the brocken wire, I've no idea...
Thanks for checking. The taped connector is for electronic trailer brakes according to my research. So you're saying your foam covered pad wire is actually connected to the negative post!?
I've spent the whole arvo removing the entire rear battery area and checking everything as well as bcm connections. I think this will be an auto electrician job...
 

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Yes, the foam covered wire is connected to the battery negative just like your photo :cool:

In your case, as a conformation, you could have been able to hold the broken part of the eyelet against the bit that's still attached to the post. You'd have then been able to confirm if the tear in the two parts of the eyelet actually matches :cool: If you have old eyes like mine, a phone camera can be used to zoom really close to compare the tear marks in the two parts :rolleyes:

It's like in the movies where a criminal is given 1/2 his money now and the other 1/2 after thje job is complete... litterally he gets 1/2 as the money is torn in two... and often he's seen matching and sticking the money together as the police raid his house :p:p:p
 

dassaur

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Yes, the foam covered wire is connected to the battery negative just like your photo :cool:

In your case, as a conformation, you could have been able to hold the broken part of the eyelet against the bit that's still attached to the post. You'd have then been able to confirm if the tear in the two parts of the eyelet actually matches :cool: If you have old eyes like mine, a phone camera can be used to zoom really close to compare the tear marks in the two parts :rolleyes:

It's like in the movies where a criminal is given 1/2 his money now and the other 1/2 after thje job is complete... litterally he gets 1/2 as the money is torn in two... and often he's seen matching and sticking the money together as the police raid his house :p:p:p
Classic haha.
thankfully I did check them and they mate perfectly. I thought it may have needed to be disconnected with the trailer module or similar and they did a bodge job of it.
 

dassaur

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For anyone who has this issue - solution to follow
For some reason a BCM fuse was missing from the driver's fuse box. I have no idea how that happened.

The black cable should be connected to the negative post, it is the battery monitoring cable.
So joyfully all my codes are gone!!
 

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It looks potentially related to tow wiring but can't be sure. While we're at it, that taped up connector - anyone else got it?

Thanks !!!

Those two cables are for people who install electric brakes for trailers. The smaller gauge cable (purple with white stripe) has 12 volts on it when brakes are applied, so that will go off to a brake controller to let the unit know the brake pedal has been pressed.

The blue cable comes back from the electric brake controller and goes down to your external 7 pin (or 12 depending on your setup) trailer plug to go off to the trailer brakes.

I wired up my Redarc Towpro Elite through this switch, made life so much easier than having to dig for these two cables elsewhere in the car.
 

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When you reconnected the battery, did you connect negative first, or last?
 
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