Today at Atelier Kaz - ex-Honda R&D, F1, Indy/CART engineer

After 3 years, finally, I’m going back to the normality but very slowly.
Losing internet access at the end of last year and into the new year for about 7 days was inconvenient but at the same time, very refreshing.

Injured left foot and still limping but just need to live with it.

Will be joining the indoor setting from now on but I’m afraid not inviting people inside the house or inside the garage so no coffee or tea served unless outside.
Please take break on the way to/from my place.





And I think my NSX sensed the change and wanted to be looked after.

After more than 170Kmiles and into the 29th year, for the first time, the brake light switch failed.

On leaving the garage, normally, I would see the reflection of the brake lights.
However, on this occasion, there was nothing and not even the famous ‘BRAKE LAMP’ warning on the dash.

This meant that there was no power to both of the failure detection circuits and thus, none of the brake lights were operating.
Interestingly, it was fine like 10min ago while working on the other area of the car.

So, it can only be the fuse or the switch.
Horn (fuse shared with brake light) sounded fine so it’s not the fuse.

Next, the brake light switch.

Shorting the 2 wires at the mating connector triggered the brake light properly so it could only be the brake light switch itself.

By the way, found another mistake in Japanese Workshop manual. The layout of each terminal was wrong.


Many owners reported the brake lights staying on permanently due to cracked grommet at the pedal stopper.
However, not many reports of brake light switch failure on our NSX although enough reports from other makes/models.






With the multimeter, confirmed that the switch was faulty so opened it up.





Inside of the black cylider body with 4pin 250 (spade) male terminal.

The white section is the centre terminal and spring loaded.

Under normal condition, the centre terminal is pressed against the 2 brass terminals (behind the yellow marking) creating good continuity.

Inside the switch body, there is a small plunger and it also has small spring.

The two silver metal plates are for the cruise control (marked blue) brake input.










Tried to de-solder the terminal blades to slide them out from the housing but they just didn’t want separating.

Gently pried the 90deg brass terminal to release the centre terminal.

One of the terminal surface was burnt and in really poor condition.






When the brake pedal is resting against the stopper, this plunger pushes the white centre terminal away from the brass terminals resulting in open circuit.

Thus, the brake light is only activated when the pedal is operated.

However, with the faulty switch, part of the white insulator got melted and trapped between the centre and the brass terminals and not allowing the brake light circuit to close.

It got worse and worse that it resulted in angled contact causing arching and made one of the terminal sueface very rough.

Glad that I spotted the failure before driving.






As a side note, my NSX is equipped with the cruise control so this brake switch also has separated terminal to detect the brake pedal operation.

It becomes open circuit if the brake pedal is operated resulting in cancellation of the cruise control.

These 2 silver spring arms slide over the silver metal plate that you saw in the 3rd photo above (blue arrow).

At the silver metal plate, there is a window that will create open circuit when the brake pedal operated.