Zumo User Forums

Hello,
I am able to charge up my 390LM, no problem on the USB cable, when I’m at home. The problem comes when I connect the 390LM to my motorcycle, with the compatible cradle which is hardwired to the motorcycle.

From the totally OFF position, the 390LM will turn on by itself, when I put the ignition to the ON position (totally normal and expected), but then it does not continue to charge the 390LM. No lightning indicator at all. It just runs on the battery with no charging from the cradle. I’ve also tried the WD-40 trick, no luck.

Thank you in advance for your suggestions and help!

Welcome to the forums.

Sorry to hear about your charging woes.
I don't know the 390 LM, but often such issues are to do with the pin contacts that the Zumo uses when it is mounted int he motorcycle cradle.
Not making contact, spring not springing them back, dirty contacts ....

Someone that knows what they are talking about may be along to help soon !

I had exactly the same problem on 396. I did all possible troubleshooting and tests. In the end I gave up and ditched the cradle. Using a cable to a 3.0 usb port. No issues. I still using the cradle but without its cable and widened the opening in it where the usb cable connecting to the unit, but using a phone holder with ram mounting boll will work too.
This is a known problem with 396 cradle.

Thank you. I was afraid of hearing that option. It seems fair to assume that there is power to the cradle, but the contact from the pins to the back of the 390LM appears to be inconsistent.

I have a 396, a 390 and a 395 and the Garmin cradle and power harnesses mounted on four different bikes. On three of these cables I was getting frequent "power lost messages" while riding. I have solved this by adding a strip of electrical tape to the cradle opposite the two pin connector to make the connection tighter. I beleive without this shimming the motorcycle vibration causes the electrical connection to be lost.

I suggest you try this shimming, maybe it will solve your problem.

lather wrote: ↑Mon May 22, 2023 3:22 pm I have a 396, a 390 and a 395 and the Garmin cradle and power harnesses mounted on four different bikes. On three of these cables I was getting frequent "power lost messages" while riding. I have solved this by adding a strip of electrical tape to the cradle opposite the two pin connector to make the connection tighter. I beleive without this shimming the motorcycle vibration causes the electrical connection to be lost.

I suggest you try this shimming, maybe it will solve your problem.

Thank you for sharing your experience and the helpful tip! It's great to hear that you found a solution to the "power lost messages" issue with your Garmin devices. The electrical tape shim sounds like a practical and effective way to address the problem caused by motorcycle vibrations. I'll definitely give it a try and see if it helps improve the connection on my setup. Thanks again for the suggestion!

Fxwheels wrote: ↑Tue May 16, 2023 6:02 pm I had exactly the same problem on 396. I did all possible troubleshooting and tests. In the end I gave up and ditched the cradle. Using a cable to a 3.0 usb port. No issues. I still using the cradle but without its cable and widened the opening in it where the usb cable connecting to the unit, but using a phone holder with ram mounting boll will work too.
This is a known problem with 396 cradle.

It's unfortunate that you experienced issues with the cradle for the Garmin 396, but it's good to know that using a direct USB cable connection or a phone holder with RAM mounting works as a workaround for the problem. Thank you for sharing this information about the known issue with the 396 cradle.

If you are forced to continue to use the USB socket to power the unit when on your bike, then try to find a way to secure the cable to the bracket or to the Zumo case. The problem with USB sockets is that the connection to the circuit board is not particularly robust, and although the cable will sit in the socket firmly, the vibration of the power cable on the motorbike will be passed to that weak link to the board.

So somehow, the cable needs supporting against the case of the Zumo, so it doesn't pass vibration to the USB connection.

lather wrote: ↑Mon May 22, 2023 3:22 pm I have a 396, a 390 and a 395 and the Garmin cradle and power harnesses mounted on four different bikes. On three of these cables I was getting frequent "power lost messages" while riding. I have solved this by adding a strip of electrical tape to the cradle opposite the two pin connector to make the connection tighter. I beleive without this shimming the motorcycle vibration causes the electrical connection to be lost.

I'm trying to mentally picture where on the 396 cradle you add a strip of electrical tape. I'm soon getting a 396 and want to do that to mine when it arrives. that 2 pin power connector is held in the cradle by a screw from the back of the cradle? where does the electrical tape go?

The tape is wrapped over the protrusion on the bottom of the cradle where the slot on the GPS fits. Here is a picture: Warning: If you add the tape it becomes a bit more difficult to insert the GPS into the cradle and if you are not careful it may not be fully locked in.

Just make sure the unit is fully locked in before riding off.