Unable to secure red terminal on 12V LVB

[Gimme_my_MME]

Well, found the part. Definitely not a small piece to replace. Looks like it's the entire cable assembly. I'll try to call the local mechanic to see if they can accommodate me.

I wonder if you can get the part from one of the crashed cars, since you don't need the whole unit as it's sold. Not sure how you would go about getting it though

 

[louibluey]

I think I see what happened. I have tremendous respect for people who take on DIY projects, please take no offense. Also, I feel your pain having to explain what happened to your wife and to deal with the problem and rental.

For others who might later read this thread, on both terminals, the screws that tighten the clamp are always used only for the purpose. They cannot be removed. As you now know, the positive terminal screw has intentionally deformed threads at the end, so that it cannot be removed. Unscrewing past that point might be what caught the nut and broke it free. These screws should only be loosened, and just opened enough to where the clamp can be removed.

Another note, wires should only be added to the electrical terminals on the positive clamp, for example, many of us have added a #8 wire with a nearby fuse to power the @markboris subwoofer project. To access those terminals, you have to pull all three top plastic panels, then remove the frunk tub. The positive terminal is not completely open to access any other way.

Return paths are generally connected at any of the approved points on the chassis as noted above. But, I understand some might want to tack on one of those two wire 12V monitors. Unfortunately, with our battery terminal clamp systems, it is not a good idea to use those screws as an electrical terminal. It might work if the screw is just loosened and not removed, but probably not a good idea.

I disagree just a little on quality. My current feeling is that the batteries are mostly fine, and there are some situations where MME is not properly charging / maintaining the 12V battery. I do not think we have a battery quality problem in general (some may be bad, or killed by MME), but generally, I think our batteries are good. At least the early ones were manufactured in Germany.

Also, the clamp for a non-military vehicle, is actually pretty good IMHO. The problem is just that that screw is designed to be only loosened, and to be held captive by the intentionally damaged or distorted threads at the end. It is only intended to be used snug tight or loosened a few turns, and never run to the end, or removed.

 

[gordonf238]

I think my biggest issue here is they the bolt cannot be removed and replaced. Simply put, the nut, which is interlocked inside the mechanism is designed not to let the bolt come off. So if the treads are stripped, there is no way to re-secure the positive battery terminal to the battery.

In any other mechanism, I would just replace the bolt / nut and call it a day.
My second issue is with how easy it was to strip the treads on the mechanism. I did not use excessive force, and only a 1/4” hand held wrench with socket.
I’m going to Jerry rig a solution with a C clamp from Home Depot to put tension on the terminal eyelet and hopefully that works. I’ll post an update.

 

[Mach-Lee]

Yes, NEVER FULLY REMOVE battery terminal clamping nuts/screws as it is common for them to be "captive" on modern designs and not fully removable without causing permanent damage.

Attach accessory ring terminals/wires only to other two larger nuts on the positive terminal assembly.

 

[Ford Motor Company]

Thank you.

I can remove the whole terminal (thereby disconnecting power to the vehicle).

I can't turn it around due to the sway bar. However, my fingers can't feel anything underneath. Just a smooth metal. I tried using a flat screwdriver to push the sides in but the bolt just won't latch. Keeps spinning in place.

Really quite silly to be honest, as I'm just about out of patience. The last thing I want to do is drive it to the dealership and look like a completely dummy.

But without the terminal secure, the car isn't really safe to drive as any large bump can cause that terminal to just pop off.

I'm just scratching my head here.

Hi there! Can you send us a PM with your VIN and Ford dealership information? I’d be happy to look into this on my end.

 

[dtbaker61]

Understood, but you only need to take out the frunk tub (a big job the first time). I have never needed to remove the structural bar.

Also, there is a little green/red plastic part over on the right side that disables the HV. It is good practice to open it whenever removing a clamp from the LVB because it turns off, or prevents the DC/DC converter from coming on.

This is in the "open position". It is good to never remove either terminal from the LVB without first opening this interlock switch. I thought it was silly at first, but now understand why they want you to open it (to protect the DC/DC converter). This is under the right side removable panel.

this HV disconnect REALLY should have a clearly labelled access port in top covers for emergency responders in case of accidents... I sure as heck would want to disconnect HV before using 'jaws of life' for an extraction cutting thru any areas where there might be HV cabling.

Responders should have easy access to a 'cut loop' without having to read a manual. This is not really a cut loop since it just opens a contact, but it's better than nothing.

 

[dtbaker61]

Yes, NEVER FULLY REMOVE battery terminal clamping nuts/screws as it is common for them to be "captive" on modern designs and not fully removable without causing permanent damage.

Attach accessory ring terminals/wires only to other two larger nuts on the positive terminal assembly.

in the case of the MME, you should avoid installing anything on the terminals.... use the (separate) 12v connection points

 

[gordonf238]

Yes, NEVER FULLY REMOVE battery terminal clamping nuts/screws as it is common for them to be "captive" on modern designs and not fully removable without causing permanent damage.

Attach accessory ring terminals/wires only to other two larger nuts on the positive terminal assembly.

Oh, understood. No argument here. The negative terminal has a similar mechanism except the bolt and nut can be replaced.

For a 12V battery - which is user serviceable and replaceable (you’ll see many threads here that focus on dead LVBs) a positive battery clamp to have failed so easily, and essentially rendering the vehicle useless is a bit of a poor design in my opinion.

Let’s see that I can Jerry rig, as no mechanic shops that I frequent have any interest in fixing this.

Sponsored