di2 DQs

OK, I got all the di2 parts that should work, but when I push the shift buttons, nothing happens. I’ve got it wired up thusly:

To A junction

To B junction

To battery and dangler

What am I doing wrong?

The A junction has a button and two lights that I’ve not seen light up.

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I have no fucking clue other than is the battery charged?


I will need to investigate and report back, but you are using a whole bunch of outdated Di2 shit. Get the E-Tube app on your phone and update firmware.Text me if you still have issues,

I feel like this ends with a Suntour thumb shifter and a simplex dangler.


Are the cables securely clicked in

Serious q: do you have the dumb Shimano Di2 “wrench”?

You really need to click those dudes in there

Bro this is all current

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Check your connections. God help me for saying so, but Mig is right about the Di2 tool.

First, is the battery charged?

Secondly, are all the wires clicked into the components? (They should make a little click when fully seated)

If you’re not even getting the a junction to light up, it’s possible that one of the above is not done.

You can also slowly assemble it; attach the battery mount to the a junction, then add the battery and see if the a junction lights up:

If this works, start adding components one at a time; first wire in the dangler, see if the a junction lights up, then do the same with the shifter. If all of this works, try to shift — if any of this fails, you may need to flash the firmware in the battery mount up to current versions (I’m 99% sure the firmware in the a junction & dangler is up to date, but not the battery mount and I know that a battery mount with original firmware just won’t work with anything else)

If your lbs is at all di2 literate, you may be able to get them to flash any out of date items to current spec (if you have a di2 programming interface you can use that + a windows pc to bring all the firmware up to date yourself). Failing that, you know my mailing address and l can flash them for you


Bro, external battery, external junction B, stem mount junction A, and a beat up 6870 RD is not current Di2 shit. No offense to Rudys issues, but Mig you might want to argue with someone else.


Nonsense. 7970 stuff is outdated, and maybe 6770 by virtue of not playing well with any of the 11 speed derailers. These components ain’t that.

If your plan is to give rudy a latest & greatest group, more power to you, but otherwise maybe stand off and let the historical reenactment set debug things?

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I appreciate all the input and will try these things as soon as I’m back in the city Monday night.

Forgive me if this was covered.

Have you downloaded etubes project and run diagnostics?

If something is amiss first thing is to confirm plugs are secure as mentioned. Then hook it up to the PC and etubes. If something is amiss you’ll probably know pretty fast. If you can’t “see” the whole system, it should be pretty evident if which wire or junction is the offender.

Good time to run a full firmware update.

My guess is it’s the battery or battery holder though. I’ve seen a lot of external ones shit the bed.

All of this stuff is technically still supported but a bit long in the tooth. So could be a few areas.

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People keep saying this like it’s something I know how to do.
Do I need to use a real computer?


Get it here. Plug your charger into your PC.

The user interface is surprisingly solid.

Oh wait, you’re external so I’m guessing your don’t have the SM-BCR2 charger. Uh, you should go ahead and get one if you are are having issues here and plan on keeping di2 or adding some to your fleet.

It’s probably cheaper to just run by the lbs and ask them to flash it. I’d guess that if anything has out of date firmware it’s the battery mount, because that’s one thing where if the firmware is old it will just sit there like a bump on a log.

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What’s the part number on the battery mount? External battery mount contains the chipset. If said mount has outdated firmware, you’re in a bad spot.

Grab the charger. Get E tube from shimanos site. Plug it in. Update all the firmware on every component. I have seen where old battery mounts did not speak well with the newer A junction box. The A junction box that used that battery mount was the hardwired version without a charging port.

I agree with @Elliott - It’s all outdated di2 from different generations.

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Yep. And make peace with possibility of replacing your battery mount and/or battery.

But none of those components are outdated. The only component that’s from a non-current group is the dangler (and maybe the battery mount if it’s a bmr1 or 2; the dn100 is, of course, current, but pointless if it’s on a 1x rig without the bluetooth interface wart) and it doesn’t matter because they all interoperate and can have current firmware installed.

6770 is (arguably) outdated, mainly because the ew67 won’t play with mtb shifter/danglers, dn100 & 110s, and of course the bluetooth wart (and I’m kind of miffed about this because the ew90s are huge klunky things compared to the sleek little ew67s) and the first gen pure analog di2 is definitely outdated because it won’t interoperate with anything else.

When the new latest & greatest is released with its improved wiring every piece of existing di2 gear will suddenly become outdated due to Shimano changing the connectors because fuck you, but afaik that hasn’t happened yet.

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