Third Brake Light Dash Warning After LED Swap - Correct Bulb Type 1156

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Problem

After replacing the third brake light (high-mount stop light) with an LED bulb, the dash warning light stays illuminated due to the lower current draw of the LED not satisfying the bulb failure detection circuit.

Dashboard brake warning light illuminatedThird brake light functioning but triggering bulb failure warningLED bulb installed in third brake light housing

Root Cause

The MKIII Supra's bulb failure warning system detects the low current draw of an LED bulb as a burned-out filament, triggering the dash warning light. Replacing with the correct incandescent bulb resolves the warning.

Confidence

Moderate confidence — Multiple community members agreed on this solution

View Original Thread →Posted April 2022 on SupraForums.com