Cruise keeper LED 3rd brake light, 921

Finally, a simple and effective way to have all three brake lights be LEDs and keep your cruise control working. This "resistor-free" LED bulb from GTR lighting installs in the 3rd brake light (AKA CHMSL) position and has resistance built-in so the cruise control will still function. On the NAs and NBs the cruise system is tied into the brake light circuit and will cease to function if you replace all three brake light bulbs with LEDs due to their low resistance. Replacing just the 3rd brake light with this higher resistance LED is enough to keep everything working as it should while also putting out an incredible amount of light.

The 921 (T15) is the correct bulb size for most 1990-1997 third brake light housings (1997s up thru production date 12/96, on the door jamb sticker). If your 1997 Miata was produced after 12/96 you need an 1156 third brake light, shown below.

The LED color is red, so you won't get the "pink" appearance of white light behind a red lens.

Manufacturer rated lumens: 1200 lumens.

Please note that adding a resistor instead typically won't work, as the resistor will most likely overheat and fail.

We've had a very small percentage of customers have issues with this bulb (bulb lights up fine but cruise still won't work), and the vast majority are using off-brand / budget LED bulbs. There appear to be some car-to-car discrepancies, but we highly recommend using bulbs sold by us as it's far more likely that everything will work correctly (no, this isn't a ploy to sell more bulbs!).