Thetford Toilet: “Yellow tank LED”
info RV toilet warning lights
What it means
The tank-symbol LED glows solid yellow/amber. This is an informational level indication: the system is powered on and the holding tank has reached at least the mid-level (about half full). The toilet still flushes normally; this is an early heads-up that a dump will be needed soon.
Most likely causes
- Holding tank has filled to the mid-level sensor (roughly half full) most likely
- Mid-level sensor probes partially fouled with residue giving an early reading less common
Safe checks you can do yourself
- Cross-check against the RV's main tank monitor to confirm the level is plausible.
- Plan to dump before the level reaches the high (red) sensor.
- If yellow shows with a known-empty tank, clean the tank and sensors.
How to reset / clear Yellow tank LED
- No reset needed; the light returns to green automatically once the tank is dumped below the mid-level sensor.
When to call a technician
Yellow persists even though the tank has just been emptied, suggesting a fouled or faulty mid-level sensor.
Applies to
Tecma Silence Plus 2G · Tecma Elegance 2G · Tecma macerating RV toilets with single tank-symbol wall switch
FAQ
What does Thetford Toilet code "Yellow tank LED" mean?
The tank-symbol LED glows solid yellow/amber. This is an informational level indication: the system is powered on and the holding tank has reached at least the mid-level (about half full). The toilet still flushes normally; this is an early heads-up that a dump will be needed soon.
How do I reset Thetford Toilet Yellow tank LED?
No reset needed; the light returns to green automatically once the tank is dumped below the mid-level sensor.
What is the most common cause of Yellow tank LED on a Thetford Toilet?
The most likely cause is holding tank has filled to the mid-level sensor (roughly half full).
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Sources
- Tecma 2G Silence Plus Toilet RV Owner's & Installation Manual — 98269 Rev. E, Operation — Symbol lighted Yellow = system ON and tank at least half full (A.4-4) (Thetford Corporation)
Note: This is a level indicator, not a fault. Exact half-full threshold depends on where the mid sensor is mounted on the specific tank.
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.