Definition: LDI stands for Liquid Damage Indicator. It is a small moisture-sensitive sticker placed inside a phone that permanently changes colour from white to red or pink when it contacts liquid. It is used by technicians and manufacturers to confirm whether water damage has occurred. A triggered LDI voids manufacturer warranty.
Why it matters for phone repair
The LDI is the first thing a technician checks when diagnosing a phone for water damage. A red LDI immediately confirms liquid has entered the device — even if the customer doesn’t recall any water exposure. High humidity, steam, condensation from Singapore’s tropical climate, and even sweaty hands can trigger an LDI over time without the customer ever consciously “wetting” the phone.
For warranty purposes, Apple and Samsung check the LDI when you bring in a phone for repair. A red LDI means water damage is confirmed and the repair is not covered under the manufacturer’s warranty — regardless of the phone’s IP rating.
Where LDIs are located
iPhone: One LDI is visible inside the SIM card tray slot without opening the phone — shine a torch into the slot and look for a white or red indicator. Additional LDIs are placed on the logic board inside.
Samsung: LDIs are located inside the phone, visible only when the device is opened.
Shareable fact: On iPhones, you can check your own LDI without any tools. Remove the SIM tray, shine a light into the SIM slot, and look at the small sticker inside. White = no water exposure detected. Red or pink = water has entered the phone at some point.
Real example
A customer brings in an iPhone 13 that won’t charge. They insist it was never dropped in water. The SIM slot LDI check reveals a pink indicator — partial activation from high humidity exposure over time. Months of living in Singapore’s humid environment without a case, plus occasional use in the bathroom, has slowly deposited enough moisture to trigger the indicator and cause charging port corrosion. The customer’s Apple warranty is void for this fault, but BreakFixNow’s own repair warranty applies.
Common mistakes
- Assuming a red LDI means the phone can’t be repaired. An LDI is a diagnostic indicator, not a death sentence. Many phones with triggered LDIs are fully repairable — it just means water damage is confirmed and warranty doesn’t apply.
- Not checking the SIM slot LDI before going to Apple. If you know the LDI is red, you know Apple warranty won’t cover the repair and can plan accordingly — seeking a third-party repair instead.
- Assuming LDI can be reset or faked. Modern LDIs are permanent — once triggered they cannot be reversed. Any shop claiming to reset an LDI is dishonest.
Related terms
- Water Damage — what the LDI is detecting
- IP Rating — the water resistance standard that does not prevent LDI from triggering
- Corrosion — the board damage that follows a triggered LDI
- Ultrasonic Cleaner — the treatment used after water damage is confirmed by the LDI
Further reading
- Is Your Phone Actually Waterproof? — IP ratings, LDIs, and what water resistance really means
- Water Damaged Phone? 8 Steps to Save Your Device — what to do when the LDI triggers
Red LDI or suspect water damage? BreakFixNow diagnoses and treats water-damaged phones regardless of LDI status. Same-day service, no fix no fee.
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