Lasting Damage From Intentional Short Circuit?

[mongolodeon]

Today I picked up my 2022 PowerBoost Limited from a dealership and found that they had not solved a problem where the SYNC system cannot check for a software update (which is a separate issue altogether). They brought the master tech out to the parking lot and he attempted to reset a module(s) hoping that it would do a complete enough reset to cause SYNC to fully reboot and then be able to check for an update OTA.

To do this he disconnected the negative cabling from the 12V battery and left the positive side connected. Then he took a small wire with alligator clips at both ends and clipped one end on the positive terminal (still attached to the battery post) and with the other end tapped it on the negative wiring (which was not attached to the battery post). There was a small puff of smoke and we heard some clicking from the engine compartment and the master tech was clearly surprised by this, remarking that "there must be another battery" and then mumbled about how there's another very small battery for the GPS antenna but that it shouldn't have caused what occurred. He didn't try again, so it was just the one time and it was fairly brief.

He then told me to start the truck and it started normally, but SYNC had not done a full reboot as he had intended and the software update page still just hung, trying to check for an update. He then said to bring the truck back for another appointment and he'd do a manual software update of SYNC using the shop laptop. The truck behaved normally for a few short trips after that.

Has anyone ever heard of something like this and is it possible that the technician did something that damaged the truck (electrical system, hybrid or 12V batteries, other sensitive modules) but won't be apparent right away? I would never think to do something like that but given that the service advisor brought him over and introduced him as a master technician and the most knowledgeable person in the service department regarding the PowerBoost and SYNC systems I deferred to his experience and expertise- yet I am disturbed by his reaction and surprise at what happened and it was clear that it wasn't the result he expected.

Just want to make sure my truck is not now compromised in any way as a result. I also plan to bring it to a different dealership to try to resolve the software update issue.

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[fordtruckman2003]

WTF.

Sending +12v the wrong way into the trucks electrical system is the dumbest thing I've ever read.

Second battery on all PB is under rear seat.

 

[Kanuck]

That was not a tech, that was pure stupidity. Back feeding power to any DC cct is a great way to wipe out a module costing big bucks. I would be in the owners office ripping him a new one for having that tech as an employee.

 

[Darrell78]

What he was doing was somewhat correct. But he needed to disconnect the battery under the rear seat aswell to do it. Probably didn't do any damage. If he blew the fuse for the smaller battery in the back you would have a charging malfunction come up on the dash pretty quick. You need to go into sync and see if your modem serial number displays. If not you have a TCU issue. The TCU is what receives all the info for the updates. He was trying to discharge the system capacitors. He wasn't back feeding power.

 

[Darrell78]

I wouldn't get mad at the guy. He just missed the it was a power boost. You being out in the parking lot and him being dragged out there off another job to do you a favor and he missed it being a powerboost. At least he was out there helping you. Btw have you done a reset yourself though the sync screen. It's in there somewhere. I'd be trying that first before anything else.

 

[Kanuck]

I understand the theory but I don't understand why he would do that to discharge any caps. I would think just leaving the battery cable off, the caps would bleed down quickly. Shorting out caps, I have done many times. But at the cap terminal, not at the supply.

 

[tsigwing]

What he was doing was somewhat correct. But he needed to disconnect the battery under the rear seat aswell to do it. Probably didn't do any damage. If he blew the fuse for the smaller battery in the back you would have a charging malfunction come up on the dash pretty quick. You need to go into sync and see if your modem serial number displays. If not you have a TCU issue. The TCU is what receives all the info for the updates. He was trying to discharge the system capacitors. He wasn't back feeding power.

there is a 125A fuse for that small battery under the seat. Don't ask how I know.

 

[Porpoise Hork]

More like a master dipshit if you ask me...

 

[Mtntrls]

I wouldn't get mad at the guy. He just missed the it was a power boost. You being out in the parking lot and him being dragged out there off another job to do you a favor and he missed it being a powerboost. At least he was out there helping you. Btw have you done a reset yourself though the sync screen. It's in there somewhere. I'd be trying that first before anything else.

Doubt it’s in the service manual esp for a Powerboost. Even if aux battery had been disconnected, I’d be mad.

 

[mongolodeon]

I made this post because I look at what he did like most of the others here saying what a dipshit the "master technician" is. But, since that doesn't necessarily lead me anywhere I'll focus on the coupla responses that I hope (pray?) are the case.

What he was doing was somewhat correct. But he needed to disconnect the battery under the rear seat aswell to do it. Probably didn't do any damage. If he blew the fuse for the smaller battery in the back you would have a charging malfunction come up on the dash pretty quick. You need to go into sync and see if your modem serial number displays. If not you have a TCU issue. The TCU is what receives all the info for the updates. He was trying to discharge the system capacitors. He wasn't back feeding power.

This makes sense to me based on his reaction. He was surprised and stated that "there must be another battery somewhere.... the small battery for the GPS antenna shouldn't have done that..." are what I remember. I believe you and the others who say there's a small battery under the rear bench and I do remember seeing a box of some sort there. Just so I understand, this is a small battery and unrelated to the hybrid batteries?

Forgive my ignorance but you sound like you know a lot more than I do about these electrical systems. I'd be relieved if indeed this incident did not do any damage as you say, but can you please help me understand better why you think it didn't do damage? It'd be reassuring to understand the reason(s) why I don't have to worry about what was done by the guy.

I wouldn't get mad at the guy. He just missed the it was a power boost. You being out in the parking lot and him being dragged out there off another job to do you a favor and he missed it being a powerboost. At least he was out there helping you. Btw have you done a reset yourself though the sync screen. It's in there somewhere. I'd be trying that first before anything else.

He definitely was pulled off another job unexpectedly by the service advisor. They had the truck for 2 days to fix the software update hanging issue and when I got the key back I started the truck and went right to that software update page in SYNC and it was still hanging, so I went back in to the service advisor and asked why they had me come back to pick up the truck when the issue wasn't resolved. He said that there were only two techs qualified to work on the PowerBoost hybrids and that the other one (lower qualified) had updated 10 modules' software and replaced a speaker. I was like "that's great and I appreciate updating the other modules but the only one that's customer facing and the one I brought in to update... wasn't updated". So, he went and grabbed the Master Tech who he said is the most knowledgeable about hybrids and PowerBoost and the guy said that they had to use the shop laptop to do an update of SYNC but that he wasn't available for about a week. I said I planned to leave town with the truck for quite awhile in 5 days (they had already had the truck a total of 4 days over the span of the week prior for some other service items). At that point the Master Tech started asking me if I had tried this and that, such as disconnecting the negative terminal for 10 minutes, which I had (for a half hour). After it was clear I'd tried all the straightforward fixes he started telling me to take a small wire to do XYZ and when I said I didn't feel confident doing that he went and got a wire and did it himself. I'm pretty sure he knew it was a PowerBoost as we three were discussing it as a hybrid.

I did do one of the two resets in SYNC (I think it just reset all the connectivity stuff, not the entire SYNC system), and that didn't do it.

I understand the theory but I don't understand why he would do that to discharge any caps. I would think just leaving the battery cable off, the caps would bleed down quickly. Shorting out caps, I have done many times. But at the cap terminal, not at the supply.

Yes, I found that advice and had tried disconnecting just the negative terminal for 30 minutes to try to get everything to fully reboot and it didn't work. This was before I brought the truck in for service.

What started all of this is I brought the truck in for an oil change and when I got it back my custom menu was reset to default which has happened in the past. When I went to go play the stereo for the first time I got the loudest electronic screeching/snapping/popping/zipping sound (hard to describe) that blew out our eardrums. My ears were literally ringing for several days from it. That's what made me initially check into the software update and found that the last time it was updated was May 2024. I spent an entire evening trying everything I could find online about how to get past the hanging "checking for software update" spinning circle and exhausted all options so I brought it back to the dealership and that's when they began updating the software of various modules and I guess the technician also heard a popping sound from a front speaker so replaced it. It seems they did everything except address the actual issue I brought it back for, the hanging software update.

Now with having done what the Master Technician did and the puff of smoke, I am worried a mountain is being made out of a mole hill and now I'll have serious electrical issues or compromised batteries (either 12V or hybrid) down the road. So, I've asked the service advisor to document what the Master Tech did in my paperwork so if it comes back to haunt me at least I'll have documentation of what happened.

Any further advice would be greatly appreciated. I lost sleep over this last night!

 

[HammaMan]

That guy needs fired or some serious retraining. You can't mistake the PB for another truck given the HV components and orange wiring under the hood. There's around 300k PBs out there.

How small of a wire are we talking? It'd take a bit more than a thin gauged jumper wire to pop the 125a fuse. Not sure where he got the whole short out the 12v system with a jumper, the brake pedal has been the go-to for decades. Had he done, that he would have seen that the truck was still very much still alive via the aux batt.

This is inexcusable incompetence IMO.

 

[mongolodeon]

He was using a very small/thin wire that was coated, if I had to guess I'd say it was maybe between 1/16 to 1/8 of an inch in diameter, with a little alligator clip at either end. It certainly didn't look like it was designed for the purpose.

As stupid as this apparently was, I am trying to figure out if there's any potential damage to the vehicle, whether noticeable now or even worse in the future. Should I have my batteries tested, or is there any other way to assess for possible damage?

 

[FaaWrenchBndr]

This so-called master tech is actually a master dumbass. Sounds like he wasn’t even up to speed on the power boost model at all any half train technician would know that disconnecting the main battery ain’t gonna do shit if you don’t disconnect the aux.

I would take it to another dealer and just explain what the problem is. Personally, I would not offer any of the information you posted above.

Another thing, just something to keep in mind. There is no way in hell I would partake in any kind of troubleshooting or work on my truck with attack in the parking lot not just know but hell no. There is no way I would want to be part of some backyard, wiring hack, bullshit that could possibly short out thousands of dollars of modules.

 

[mongolodeon]

I already have an appointment at another dealership to try to do the SYNC update manually. I was planning to tell them what the first dealership did and ask them to verify that there was no damage done by whatever means necessary. I also have asked the first dealership to document what they did. Are you saying this is a bad idea? If so why? (probably a dumb question but I don't want to make assumptions)

 

[HammaMan]

There's no telling what long-term issues could crop up from this. The aux batt B+ is wired into the BCMC under hood. The - portion is attached to the back of the cab and transfers energy through the cab itself. Various grounding locations are located throughout the cab much closer to where the negative battery terminal connects to the cab, where the short occurred.

I'd have this situation well documented (bitching at the dealer about it as well as calling ford corporate about it) and accept nothing less than a full extended warranty at their cost.

Everything from the PCM to APIM and everything up at the front of the truck may have shortened life. The battery isolator could also end up with issues as the short went through it. The PB was designed to not even pass ICE starting transients into its electrical system (everytime the truck starts while rolling the entire electrical system is isolated from the underhood batt).

There could be random issues that just start showing up immediately or they may end up presenting at a later date. There's no way to quantify the stress this event placed on the various ECUs within the truck. The 7ah batt isn't large and a short like likely quickly dipped the voltage well outside of expected norms.

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