Zumo User Forums

POST NOTE - the situation regarding the screen brightness going off and on is also related to the same supplied power to the Zumo unit. The fuse would cut out and than cut back in with direct hard wire electrical power from the motorcycle battery. However, the Zumo GPS unit is built with a default to reduce the screen brightness from 100% to either 80% or 60% when ever on internal battery. Therefore, your Zumo is jumping from full motorcycle battery power to internal battery power. Back and forth. Your unit will respond with either full shut down - Power up and down - Screen brightness full or dim. The replacement of the fuse in the wiring harness may take care of all the problems mention in this forum.
Suggest you verify in your unit that the check box under Screen Brightness is not checked to dim under internal battery power. Besides, the amount of power available off the internal battery is really only 20 - 30 minutes - depending how dim you make the screen.
Lastly, I am in full agreement that the Garmin Zumo 595 screen brightness is really not acceptable for riders outside and exposed to bright sunlight. I asked Garmin if there was a way by software update to make the light output brighter when the GPS unit is running off of direct battery power, Their reply was no. Guess enough Zumo owners complained enough to get their attention to fix this issue.
Garmin's new XT version is acceptable for viewing and my daughter's Zumo 396 unit is also acceptable.

Thanks Ramrod.

Unfortunately, the 396 charging mount has Garmin's fusebox which eliminates replaceable fuses so it's not as easy as replacing the fuse. I wonder if the new fusebox has a problem?

https://support.garmin.com/en-US/?faq=o ... JgBG53B9NA

The 'Link' you provided in your reply on the power wiring harness for direct power via motorcycle battery makes me wonder why Garmin would go into a modified product design effecting 4 Zumo model numbers. Was it for a cost savings or repair a design flaw?
New design harness has to be disconnected from the positive battery post to allow for a reset.

https://support.garmin.com/en-US/?faq=o ... JgBG53B9NA

Either design still has only two wires to obtain power for the Zumo via direct battery connection. Power from the wire harness is secured to the mounting plate bracket. The bracket holds the power wire plug end with two points of contact to the Zumo. Are these two 'pins' really making full contact all the time? Perhaps a piece of 'shim' material inserted into the bracket could put more holding pressure on or behind the power plug to the Zumo. This setup is direct for power flow. Interference could be a pinched/cut wire during installation. Damage to the wire insulation forming a random grounding due to a sharp metal edge. Heat from the engine or exhaust pipes affecting the Zumo directly. If 'hot' power wire is attached to the motorcycle fuse box as an additional precaution - reinsert wire end or select another fuse bracket location and monitor the Zumo. You will find the cause in the end - Zumo unit itself or the wiring harness. Good luck.

My daughters Zumo 396 with the new design wire harness (no fuse) has been working with out any power issue all summer.