Electrical failures are invisible until they are not: you cannot see your own brake light, and nobody tells you. A two-minute weekly check catches nearly all of it. The legal side — what equipment the law requires on a bike — is covered in motorbike-required-equipment-vietnam; this is the practical walkaround.
The weekly walkaround
Ignition on: front low and high beam, rear light, both brake-light switches — lever and pedal each, checked against a wall’s reflection or a helpful glance backwards. Indicators, front and rear, both sides. Horn. Number-plate light — the legally required item that dies unnoticed most often, hidden at the back where nobody looks.
The humidity factor
Vietnam’s damp creeps into connectors and earth points: the classic symptoms are intermittent faults — a brake light that works only when it rains, indicators that need a wiggle. A spray of contact cleaner on accessible connectors, done during a service, keeps most of this away. If you park outside in the wet season, expect wiring to age faster than in a garage.
Bulbs you can fix yourself
Headlight and indicator bulbs are mostly tool-less or one-screw jobs; carry the right spare if you ride at night often — night-riding-motorbike-safety-vietnam covers why a dead headlight ends the ride legally as well as practically. Touch halogen bulbs with a cloth, never fingers.
Wiring that needs a workshop
Anything beyond a bulb: melted connectors, a charging fault (battery never full despite riding — battery-care-motorbike-vietnam covers the symptoms), a horn that fades with revs. Vietnamese electrical shops are fast and inexpensive; hand them the symptoms, not a self-diagnosis.
The one-line version
Once a week, ignition on, every light and the horn — two minutes that keep you legal after dark and visible to the traffic behind, which is where the bulbs you never see matter most.