Cannot connect Garmin sensors to Zwift

I have recently purchased a standard Tacx Booster turbo trainer. I realise the limitations of this trainer but really want to give it a go with Zwift and do some winter training in my garage.

I have a Garmin which I use when out on the road and have the sensor (I think speed sensor) which is strapped to the back hub and cadence sensor which is strapped to the left pedal crank.

I also have a Garmin HR strap monitor / sensor.

So I have downloaded the Zwift software to my laptop and have an Ant+ dongle and a 3 metre dongle /usb extension.

I have tried to get the sensors to wake up and be found by Zwift and they are just not finding them.

Both sensors worked ok a couple of weeks ago when paired with my garmin and out on the road.

In a brief moment the Zwift software found the HR sensor and then this disappeared.

Firstly, do I have everything I need and can anyone give help and guidance on how I can get the sensors to link up with Zwift.

If you need to see some pictures I can post these.


Put your HRM strap on and use your headunit (e.g., Garmin, Wahoo, etc…) to confirm that it’s working and that your heart is beating :wink: Now you know the HRM is active and working, fire up Zwift. The ANT+ icon at the top left of the pairing screen should be radiating signal rings if it seen/detected by Zwift. Some ideas for you if you’re still having issues:

Double check that the ANT+ dongle is firmly seated in the USB extension. Likewise, double check the USB extension is fully inserted to the laptop USB port. Try a different USB port. Try directly inserting the ANT+ dongle into the USB port sans extension cable.

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Thanks for the ideas. So far I have tested the HR strap and it is found on the garmin head unit and has been found by Zwift (see picture)

I have since been reading on Garmin forums that the speed and cadence sensors I have fitted to my bike may well need new batteries.

I have never changed them and it would appear they use gps when you are outside so potentially I would have never know they are out of battery.

I am hoping when I do this tomorrow I will get them to connect to Zwift.

You could easily check both the speed and cadence sensor via your head unit as well. Turn on the head unit, go into the paired sensors and see if they are there and connected. Might need to spin your crank and wheel to make them activate.

When outside, speed could be from GPS or from the speed sensor. As for cadence, indoors or outdoors, it would have to be come from your cadence sensor.

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Im new to zwift and recently downloaded the app, im trying to pair the garmin speed and cadence sensors to the ios app but the app does not find the sensors, any tips to make it work?


The Garmin sensors are ANT+ only and the Zwift App on mobile devices only excepts Bluetooth connections. You would need either CABLE or the 4iiii Viiiiva HRM to bridge the ANT+ signal to the iOS device.

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