Tesla Model Y Light Malfunction Warning: A Mouse Nest and a Chewed Harness
A 2023 Tesla Model Y came in with a light malfunction warning on the display. Behind the front bumper cover we found a mouse nest — and a lighting harness chewed through to the copper. We repaired the harness and the warning cleared. Here is what rodent damage looks like on a modern car.
2023 Tesla Model Y October 23, 2026 3 min readDocumented by Alex
How it arrived
Driven in with a light malfunction warning on the touchscreen.
Reported symptoms
Light malfunction warning on the display
Outcome
The chewed section of the Model Y’s lighting harness was repaired and protected, the nest removed, and the light malfunction warning cleared. The work carries our 12-month / 12,000-mile warranty on new parts, whichever comes first.
This 2023 Tesla Model Y came in with a light malfunction warning on the touchscreen. On a Tesla, a warning like that is the car telling you it has lost a circuit it expects to see — a bulb-out style fault, but on a car where the lights are LED modules talking to the body controllers. The question is always where the circuit is broken.
What we found
Following the circuit led behind the front bumper cover, and there was the answer: a mouse nest. The harness feeding the light ran right through it, and the mice had chewed it.
The harness behind the bumper cover. The protective loom is chewed open along its length.Close up: through the loom and into the wiring inside.
The repair
We repaired the damaged section of the harness, sealed and protected it, and put the loom back around it. With the circuit whole again, the light malfunction warning cleared. The nest came out too — leaving it in place is an invitation for the mice to come back to the same spot.
What to take from this
A warning light that appears on a car that otherwise drives fine is often a wiring fault, not a failed module — and wiring is far cheaper to fix. If the car has been parked for a while, or you have seen signs of mice in the garage, mention it: it narrows the search. We work on Teslas as an independent shop; more on our Tesla Model Y page, our Tesla service page, and our electrical diagnostics.
From the job
What we photographed
The chewed harness behind the bumper cover.Chewed through the loom into the wiring.
FAQ
Questions this job raises
What causes a light malfunction warning on a Tesla Model Y?
Anything that breaks the lighting circuit the car monitors. On this 2023 Model Y it was a harness chewed by mice behind the front bumper cover.
Do mice chew wiring on electric cars?
Yes. A parked EV is just as warm and sheltered as a gas car, and the insulation on its low-voltage wiring is just as easy to chew.
Can a chewed wiring harness be repaired instead of replaced?
Often, yes. On this Model Y we repaired the damaged section of the harness rather than replacing the whole harness, and the warning cleared.
How do I know if mice have been in my car?
Nesting material, droppings or chewed debris under the hood or behind panels, a musty smell from the vents, and warning lights that appear while the car was parked.
Do you repair Teslas in Worcester?
Yes. We work on Teslas as an independent shop in Worcester, MA, including electrical diagnostics and wiring repair.
