PPOB "Unavailable"! Fixed #49

[chl]

Update:

As of Friday (28 Aug), the service writer says that they replaced the wiring harness but it "blew a fuse"....not sure what fuse that would be...and that would indicate a short! Not good! But he said they've decided to replace the "fuse block" and a module. Of course we're not getting specifics here and maybe not the proper nomenclature. Maybe (from the drawings referenced previously) the "generic function module GFM3"151-8"? as it's labeled 7.2 kW? And maybe the rear H.V. junction box?
I really don't know....but he said they should have the parts by Monday. I'm crossing my fingers.

OMG...what a mess.

Blown fuse = short circuit somewhere, a short to ground.
That's a new wiring issue isn't it?
No fuse blown before, right?

Good grief!

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[dmd3home]

Yes, I didn't find any blown fuses previously.....though I didn't check every one. So yes, I hope they're not creating problems! But again, I'm not sure the communication between the tech actually doing the work and the service writer is always accurate. I really hate not knowing what is REALLY going on. It's so hard to leave things in someone else's hands.....I so want to be involved!
I'll keep you posted.

 

[chl]

Yes, I didn't find any blown fuses previously.....though I didn't check every one. So yes, I hope they're not creating problems! But again, I'm not sure the communication between the tech actually doing the work and the service writer is always accurate. I really hate not knowing what is REALLY going on. It's so hard to leave things in someone else's hands.....I so want to be involved!
I'll keep you posted.

Wiring issues can take a lot of time to find and fix...no choice but to remain patient - I'd have a hard time doing that as well. Good luck!

 

[dmd3home]

Final Fix!

Got the truck back yesterday (Thursday, 3 Sept) .....and everything works!!! I've attached here a copy of the final invoice. Of course this is warranty work so no $ amount is listed...though I'm told it would have been about $2800 (I would have guessed much more). Although, again, it's difficult to really know what went on as I'm not talking to the actual technician that performed the work and just speaking with the service writer and reading the invoice, but it appears that the issue was the 7.2 kW inverter. The invoice however calls it the DC/DC converter in the parts list....though in the written portion calls it the GFM3. My research (from info provided in this thread) shows the GFM3 as the "generic function module 3" which, in my interpretation is the 7.2 kW PPOB inverter itself (generic function module? Really? Why not call it what it is?).

Drawings show the HV inputs from the HV junction box feed through pins 1 and 4 into GFM3 (the 7.2 kW inverter). Checking at these pins was the key to finding the issue. It is interesting, and was a surprise to the tech, that the HV junction box has its own fuses...one of which was blown. The fuse was replaced and then blew again and testing on pins 1 and 4 indicated a fault in the inverter itself.

Removing the bed made sense, but I'm quite surprised that they removed the HV battery as well.....it's still not clear to me why that was necessary....and twice at that! Although I do wonder if, when they say "removed and reinstalled HV battery" the second time they were just referring to the HV wiring connectors to GFM3. I can see that they DID indeed remove the HV battery as I can see the socket marks an the battery carrier bolts and, of course, the need to refill and bleed the coolant. I also wonder if it was necessary to replace the wiring harness. The fuses are there to protect the harness....and appeared to do that job. Oh well.

I did run the PPOB at 3 kW for about 5 hours...a good test, to verify all is working.....and it is. Yay!
I'm also pleased that my local dealer was able to handle this task as I was afraid it might be beyond their capability. It's nice that there is a direct hotline to Ford for specific procedures like this. Great to have my truck back and working!

 

[TaxmanHog]

Wyatt deserves a case of beer.................

 

[chl]

Final Fix!

Got the truck back yesterday (Thursday, 3 Sept) .....and everything works!!! I've attached here a copy of the final invoice. Of course this is warranty work so no $ amount is listed...though I'm told it would have been about $2800 (I would have guessed much more). Although, again, it's difficult to really know what went on as I'm not talking to the actual technician that performed the work and just speaking with the service writer and reading the invoice, but it appears that the issue was the 7.2 kW inverter. The invoice however calls it the DC/DC converter in the parts list....though in the written portion calls it the GFM3. My research (from info provided in this thread) shows the GFM3 as the "generic function module 3" which, in my interpretation is the 7.2 kW PPOB inverter itself (generic function module? Really? Why not call it what it is?).

Drawings show the HV inputs from the HV junction box feed through pins 1 and 4 into GFM3 (the 7.2 kW inverter). Checking at these pins was the key to finding the issue. It is interesting, and was a surprise to the tech, that the HV junction box has its own fuses...one of which was blown. The fuse was replaced and then blew again and testing on pins 1 and 4 indicated a fault in the inverter itself.

Removing the bed made sense, but I'm quite surprised that they removed the HV battery as well.....it's still not clear to me why that was necessary....and twice at that! Although I do wonder if, when they say "removed and reinstalled HV battery" the second time they were just referring to the HV wiring connectors to GFM3. I can see that they DID indeed remove the HV battery as I can see the socket marks an the battery carrier bolts and, of course, the need to refill and bleed the coolant. I also wonder if it was necessary to replace the wiring harness. The fuses are there to protect the harness....and appeared to do that job. Oh well.

I did run the PPOB at 3 kW for about 5 hours...a good test, to verify all is working.....and it is. Yay!
I'm also pleased that my local dealer was able to handle this task as I was afraid it might be beyond their capability. It's nice that there is a direct hotline to Ford for specific procedures like this. Great to have my truck back and working!

Glad it is finally fixed!

The HV Junction box is inside the HV battery 'tub' which is why they had to remove and reinstall the HVB.

For the 240VAC to be powered by the 400VDC HVB, some reduction in voltage from 400VDC to has to be done one way or another.

The 240VAC system for the bed actually uses two 120V inverters synchronized to produce the split phase (180 degrees phase difference between the hots) 240VAC output.

Now I don't have all the details, but some DC-DC conversion might be done separately from the AC production, that is, maybe the 400VDC is stepped down with DC-DC conversion like how they provide the DC 14V for the AGM '12v" battery, and then inverted by sampling/switching techniques?

I guess they initially suspected the harness, but then found it was the HV junction box fuse had blown due to a bad 'inverter' component and not a harness short?

Wow, hope the AC output in the Fathom is designed to be easier to repair!

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