Buy Acura MDX Brake Light Switchs

A brake-light switch is a spring-loaded, plunger-style sensor bolted to a small bracket on the pedal box. When the pedal rests, the plunger is extended and the switch is open; touch the pedal and the plunger collapses, closing the circuit so the rear lamps and the brake-pedal position signal come alive. Because the signal also feeds the shift-interlock, cruise-control cancel, ABS/VSA, and engine start/stop systems, a single faulty switch can create multiple warning lights and drivability quirks. (psbrake.com)

A wiring diagram for 2004 MDX models shows the switch's power feed flowing through Fuse 47 (20 A) before heading to the gauge cluster, shift-lock relay, and PCM. (Portal Diagnostov) This same top-of-pedal layout and four-pin connector carry through later generations, though part numbers evolve from 36750-S0K-A01 on first-gens to 36750-T2A-A02 on 2014-20 trucks. The service bulletin for 2007-11 vehicles states the gap is self-set after you push the plunger fully in and twist 45° clockwise. (NHTSA Static)

• Brake lamps stay on: Owners report glowing taillights and a flat battery until they remove the fuse or replace the switch. (Mdxers)
• Stuck in Park: The gear lever may not unlock because the interlock solenoid never sees the "brake applied" signal. (Mdxers)
• Cruise cancels early / VSA flashes: Acura's forums note that the same signal cancels cruise and sets VSA or trailer-stability codes when inconsistent. (Mdxers)
• Engine won't crank: Techs on JustAnswer describe scenarios where you must mash the pedal hard or wiggle the lever before the starter relay clicks, again pointing to an aging switch. (JustAnswer)

A quick functional test is watching the brake lamps (or a scan-tool's "Brake ON" PID) while gently touching the pedal; any lag, flicker, or no-response means the switch or its circuit is suspect. A generic bench-test-probing continuity while cycling the plunger-takes seconds and is shown in this step-by-step video (see example).

On 2007-13 MDX models, the sensor twists out by hand-no tools-after you unplug the four-wire harness (watch the full process). Older first-gens use the same motion but may require removing the dash under-cover for access. Always hold the pedal up with one hand, thread the new switch in until the plunger bottoms on the rubber stop, then lock it with the 45° twist. (NHTSA Static)

Acura's brake-pedal position switch has no separate torque spec-locking tabs handle retention-but it does have a critical 0.7 mm clearance between the plunger tip and the pedal pad once installed. Too small a gap leaves the lights on; too large delays illumination and upsets ABS timing.

A bad stop-lamp switch can freeze the shift-interlock, as shown in Acura wiring for 2009 models that routes switch voltage through the "Shift-Lock Relay" before the solenoid frees the shifter. (Portal Diagnostov) It also feeds the VSA/ABS modulator, so intermittent contact may log DTC 59-1 or 67-1 and light the VSA icon. (NHTSA Static)

Honda's June 2025 recall (NHTSA 25V391) covers 259,033 vehicles-including 2023-25 MDX-because an improperly staked brake-pedal pivot pin can let the pedal shift sideways and keep the brake lights glowing. The official recall notice lists warning signs such as brake lights remaining lit when the pedal is not pressed. (PDF) Trade publication The Brake Report and Reuters both highlight the same risk and the July 28 2025 owner-letter mailing schedule. (The BRAKE Report, Reuters)

• Step on the brakes and glance at a reflection or nearby wall monthly; this confirms every bulb and the switch fire instantly. (How-to video)
• Keep interior footwell clean-moisture or spilled drinks can corrode the switch harness, especially on early-2000s trucks. (Mdxers)
• If you replace the switch, reset memory systems (radio presets, etc.) only if you disconnected the battery. (Charm)

First-generation MDX (2001-06) shares its stop-lamp switch architecture with the Acura TL of the era, while 2014-20 models adopt updated four-pin units interchangeable with certain Accord and Civic trims. (JustAnswer) Always match the eight-digit part number on the old switch or cross-reference by VIN before ordering.

Q: Where exactly is the switch located?
A: It threads into a small bracket above the brake pedal arm-look for a white or green plastic body with a four-wire connector. (Portal Diagnostov)

Q: My MDX won't shift out of Park-could this switch be the cause?
A: Yes. The shift-lock solenoid only releases when the switch sends a "brake applied" signal; if the switch fails, the lever stays in P unless you use the manual release slot. (Mdxers)

Q: Do I need special tools to replace it?
A: No. Most models require nothing more than your fingers to twist the switch out and in. A flashlight and 10 minutes of patience help. (YouTube)

Q: Will a bad switch trigger warning lights?
A: It can light the VSA/ABS warning, cruise-control indicator, or even "Brake System" text if the car detects conflicting pedal signals. (NHTSA Static)

Q: Is there a torque spec?
A: The switch locks with molded tabs-no torque wrench is used. What matters is pushing the plunger fully, then twisting 45 degrees so the built-in gap (≈0.7 mm) is set.

Q: How long does a replacement last?
A: Genuine switches routinely reach 150 k miles, but high foot-traffic, humidity, or mis-adjustment can shorten life. Checking operation during every brake-lamp bulb change is smart. (CarCareKiosk)

Q: Does the 2025 recall mean my switch is bad?
A: No-the recall targets the pedal pivot pin, not the electrical switch itself, though one symptom is brake lamps staying on. Contact Acura with your VIN to confirm if your MDX is affected.

By understanding how this small "stop-lamp" switch works-and keeping it adjusted and healthy-you keep your MDX's brake lights bright, its shifter obedient, and every safety system in sync.