I got myself a bike with Shimano di2, but I am new electric gearing. I have a problem, that Front derailleur (left shifter) is not working. Clicking any of the buttons on the left shifter, does nothing. There is no sound of gear change attempt, no lights come up on the junction box.

Right shifter (back derailleur) is working fine, I've already done ~100km on my new bike using only gears at the back. If I longer press right shifter, junction box indicates green battery light, so I assume that the battery is fine.

Seller forgot to bring me a charger, so I will not have it for at least couple days more.

I tried checking if any of the cables are unplugged, but:

  • Cable on the left shifter hoods (under the rubber) seems to be plugged in
  • 3 cables going into junction box under the stem are plugged in

I took a short video that shows what happens when I try to interact with my left shifter, it is hosted on dropbox. Sorry for the mud, it has been raining.

  • 'seems to be plugged in' isn't enough. Peel the hood back and give the cable a slight tug. It should not budge and sit really tight.You need that special Shimano tool to pull out a cable and you'll have to apply some force.
    – Carel
    Commented Nov 3, 2019 at 9:20

2 Answers 2


I've heard of loose connections between the shifters and their cables causing this sort of issue. In one case in particular, the connector didn't latch properly and the bar tape pulled it out, so it would seem OK when tested but not when riding.

In general if you've got battery and part of the system works, the connections are one of the first things to check - the front derailleur connector as well as the shifter connector. Here the lack of an LED on the controller suggests the shifter cable is at fault.

  • Yep, as always with shifter problems, check the cables. Commented Nov 2, 2019 at 20:01
  • The cable could be loose at the lever but also at the FD or in the internal junction box which sits normally in the bottom bracket housing. The best way to test the system is with the charger connected via USB to a PC running Shimano's e-tube software. It will pinpoint the faulty item. (I don't know whether the software works on a MAC.)
    – Carel
    Commented Nov 3, 2019 at 15:12
  • 1
    @Carel Shimano is a bit behind on software engineering, and even now there’s no Mac OS version of the e-tube software. Mac owners could install the wireless module and use the Android or iOS version of the software, or run Windows in Boot Camp or similar on their Macs.
    – Weiwen Ng
    Commented Nov 16, 2020 at 15:58
  • @WeiwenNg: Last year I've had a similar problem with a left shifter during an update with e-tube. While performing a firmware update the left shifter signalled failure to update, please repeat, but failed again and remained dead. Customer service replaced the left unit because it was less than 2-y-old. I've tracked the fault down to interference of the Di2-box with another USB device connected to the PC that also causes trouble with audio (shared interrupts being the cause). With e-tube connected, disconnect any non-essential USB device. to avoid trouble.
    – Carel
    Commented Nov 17, 2020 at 17:55

When the battery level falls below a certain point, front shifting is disabled.

This is by design.

Charge the battery and try again.

  • I doubt the battery level indicator would claim it to be fully charged, nor would it have enough juice left to ride a century with if this was the case.
    – Wsal
    Commented Nov 16, 2020 at 16:30
  • 1
    @WaltoSalonen perhaps not, but given they symptom and the lack of a charger, it has to be the first troubleshooting step
    – Noise
    Commented Nov 16, 2020 at 19:52

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