Door Switch Replacement

Time to install: 5 mins

Tools Required: Phillips Head Screwdriver

My interior lights failed to illuminate whenever I opened the passenger door on my Mazda Miata. Not a huge deal, but definitely more important for those with car alarms, where it’s dependent on this sensor.

There’s always a possibility that it could be a wiring problem elsewhere, but this is the most common suspect. It can be tested by swapping the driver and passenger side sensors to verify it’s the sensor itself. This fix took about 5 minutes to complete, all I needed was a Phillips head screwdriver.

Luckily, the part is very inexpensive, just under $6.00 USD new online. Regardless if it’s the driver or passenger side, the part number is S09A-66-540A.

Before starting, I ensured the interior lamp switch was set to illuminate when the door is open. The car alarm should be set to off as well.

Here’s a picture of the sensor, just held in by a screw:

Below is the location of the door switch. I removed the Phillips head screw, and pulled out the sensor. Since it was an “L” shape, I had to twist a bit, but wasn’t too difficult.

Looks pretty weather worn and beat! Pulled and disconnected the sensor from the black electrical connector below.

Replaced the new sensor and fastened it with the Phillips head screwdriver. Test the sensor to ensure the light is illuminating.

It worked!