The symptom pattern

You pick the trimmer up, pull the trigger, and either nothing happens or the cutters start and then stop again the moment you move a hand to get a better angle. The battery looks fine. Nothing’s obviously broken. This is one of the more common “my new tool is faulty” complaints on cordless hedge trimmers, and Einhell’s own manual explains why it usually isn’t — the tool is designed to do exactly this under a specific, easy-to-miss condition.

What Einhell’s own manual says

The GC-CH 18/40 Li has a two-handed safety switch: the manual states it plainly, “It works only when the switch on the steady grip is pressed with one hand and the switch on the handle is pressed with the other hand. If either switch is released, the cutters will stop moving.” That’s not a fault condition — it’s the trimmer refusing to run with only one hand on it, by design, and it will stop mid-cut the instant either hand lets go even slightly. Anyone used to a single-trigger tool can easily read this as the machine cutting out on its own.

If the cutters are jammed solid rather than just refusing to start, the manual gives a short, specific procedure: stop the equipment, remove the battery, then clear the jammed material from the blade — wearing gloves, since Einhell calls that out specifically to prevent injury.

Beyond the switch and a jam, the manual routes the rest of a no-run fault through the battery: confirm the pack is pushed fully home until the pushlock engages, then read its three-LED capacity indicator. One flashing LED means empty, not faulty — recharge it. All three LEDs blinking together means the pack is too cold to read properly; Einhell’s instruction is to remove it, leave it at room temperature for a day, and only conclude it’s “undergone exhaustive discharge and is defective” if the same blinking happens again afterwards.

Working through it

Start with grip technique, since it’s free and explains the single most common version of this complaint: both switches, one on the steady front grip and one on the rear handle, held down together throughout the cut. If the cutters won’t move at all rather than cutting out mid-use, remove the battery and check the blade for jammed material before assuming anything electrical. Then reseat the battery fully and check its LED indicator against Einhell’s table rather than guessing from how long it’s been on charge.

If all three of those check out — switches held correctly, blade clear, battery seated and showing charge — Einhell’s own fault section has only one more thing to check: that the charging unit itself was actually delivering power to the battery, not just plugged in. Past that point, the manual gives no further owner-level diagnostic or repair step at all.

Verdict

This is usually not a fault. The two-handed switch stopping the cutters the moment you shift your grip is the trimmer working as designed, and a jammed blade or a battery that needs reseating or recharging covers almost everything else. A pack that’s genuinely gone flat beyond recovery is a real repair cost, but a specific and bounded one — not a reason to assume the trimmer itself has failed. If none of these explain it, Einhell’s own documentation stops at “contact customer service,” which is the point to stop guessing rather than open the handle yourself.