Survey: High Voltage Battery Junction Box issues?

Has your car experienced a failure related to the High Voltage Battery Junction Box?


  • Total voters
    72
  • Poll closed .

Socalsp3

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Thanks for doing the analysis. I didn't realize so many have er awd. Hard so say there's a correlation.

Here they are. I think the failure counts are too low to trust that there's a strong indicator here, but there is the pattern I think one of your previous posts suggested. ER+AWD seems to be slightly more likely to have the failure. But I'm certainly not going to trade my ER+AWD in for a SR+RWD.

General population (of forum member entries into the tracking sheet):
61% ER/AWD; 19% ER/RWD; 8% SR/AWD; 12% SR/RWD

Screen Shot 2022-05-25 at 07.38.29.png


HVBJB failure population:
81% ER/AWD; 12% ER/RWD; 8% SR/AWD

Screen Shot 2022-05-25 at 07.41.50.png
 

mkhuffman

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VegStang

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Premium, AWD ER
 
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Mathington

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So far seems like ER battery and more so ER With AWD
I think we should look at the percentage of failures within each model as it's possible that there was more ER AWD models sold than others which could skew the numbers and lead to false assumptions.

If we look at the charts we can see that both SR and ER AWD models have the highest rate of this failure:

ER AWD - 23 failures over 1515 cars = 1.5%
ER RWD - 3 failures over 466 cars = 0.6%
SR AWD - 2 failures over 200 cars = 1%
SR RWD - 0 failures over 298 cars = 0%
 


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SpaceEVDriver

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I think we should look at the percentage of failures within each model as it's possible that there was more ER AWD models sold than others which could skew the numbers and lead to false assumptions.

If we look at the charts we can see that both SR and ER AWD models have the highest rate of this failure:

ER AWD - 23 failures over 1515 cars = 1.5%
ER RWD - 3 failures over 466 cars = 0.6%
SR AWD - 2 failures over 200 cars = 1%
SR RWD - 0 failures over 298 cars = 0%
I agree this is at the moment the best way to look at it. But those numbers don't lead me to believe there's a very strong connection to AWD being the (only?) culprit. I could make a physics/EE argument for why having two motors could reasonably lead to more failures in the contactors when the HVBJB seems to be identical between RWD and AWD. But the sample is just so small that I'm not convinced there's a statistical pattern.

Of course, it's entirely possible I'm wrong. That's the issue with small number statistics.
 

Mathington

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I agree this is at the moment the best way to look at it. But those numbers don't lead me to believe there's a very strong connection to AWD being the (only?) culprit. I could make a physics/EE argument for why having two motors could reasonably lead to more failures in the contactors when the HVBJB seems to be identical between RWD and AWD. But the sample is just so small that I'm not convinced there's a statistical pattern.

Of course, it's entirely possible I'm wrong. That's the issue with small number statistics.
Yea, we definitely need more data to really determine the correlation and causation. Hopefully more people respond to the survey!
 

Socalsp3

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I agree this is at the moment the best way to look at it. But those numbers don't lead me to believe there's a very strong connection to AWD being the (only?) culprit. I could make a physics/EE argument for why having two motors could reasonably lead to more failures in the contactors when the HVBJB seems to be identical between RWD and AWD. But the sample is just so small that I'm not convinced there's a statistical pattern.

Of course, it's entirely possible I'm wrong. That's the issue with small number statistics.
I think maybe a combination of ER and AWD has a higher voltage draw than either alone and no problem (so far) for cars that have neither.
 

mkhuffman

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I think maybe a combination of ER and AWD has a higher voltage draw than either alone and no problem (so far) for cars that have neither.
I think you may be right except you mean current draw, not voltage. It is the current that would likely damage the contactors, not the voltage. Limiting the current could solve the problem but then that would impact performance, of course, and may be worse than the hated five second limit. Maybe Ford will figure this out soon and let us know the path forward.
 

Socalsp3

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I think you may be right except you mean current draw, not voltage. It is the current that would likely damage the contactors, not the voltage. Limiting the current could solve the problem but then that would impact performance, of course, and may be worse than the hated five second limit. Maybe Ford will figure this out soon and let us know the path forward.
Yes sorry I meant current. Since there was an MME that had multiple HVJB failures, I think something else is stressing the HVJB to fail along with having the added stress from the ER AWD current draw.
 
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Mach-Evan

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@chrisbastow Welcome to the club no one wants to join. You'll see others with the club card in their sig. Ford CS should work with the dealership and you on getting it resolved as quickly as possible. Keep all your receipts for any costs incurred and good luck!
 

chrisbastow

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@chrisbastow Welcome to the club no one wants to join. You'll see others with the club card in their sig. Ford CS should work with the dealership and you on getting it resolved as quickly as possible. Keep all your receipts for any costs incurred and good luck!
So they got the junction box in and cannot get the high voltage to shut off so they are sending a Roush engineer to the dealership now to try and fix it.

I so miss my car!!!!
Sponsored

 
 




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