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"Brake Lamp"

Joined
12 March 2020
Messages
339
Location
California
Hey prime!
I recently installed a wing on my 1992 NSX that did not have a third brake light similar to that of the Comptech Aggressor wing and because of this i needed to snip the end off of the connector that ran through the trunk lid because it would not fit inside. First few days of driving there were no lights on my dash (besides the ABS light), now i see a "brake lamp" light. im guessing this is due to the removal of the 3rd brake light connector. Is there a way to get rid of the "brake lamp" light on the dash without the good ol' electrical tape over the light and without the reinstallation of my OEM wing and LED combo?
 
This is a little suspicious. Please check if the "BRAKE LAMP" indicator comes on directly after ignition on (or/and together with the indicator for hand brake applied even though it's released).
You could be observing the first indications of capacitor failure at the cluster - this is a serious issue that can be a cause for a fire and should not be treated lightly.

To rule that out for now you could re-attach the 3rd brake light temporarily and see if the warning goes away - it might simply be a burned out bulb or corrosion at the bulb holder :)
 
See the brake light circuit diagram below. The high mount brake light is 'indirectly' included in the safety indicator monitoring circuit. The operation of the monitoring circuit is such that the ORN/WHT wire from the safety indicator has to be pulled to ground potential to prevent the indicator from illuminating. If the voltage on the ORN/WHT wire rises above some threshold value the safety indicator will illuminate. When you step on the brakes and the four tail light brake lamps are working) 4 current sensing coils in the failure sensors close their contacts and provide a solid path to ground preventing the safety indicator from illuminating. When you are not pressing on the brakes, the ORN/WHT wire is sort of pulled to ground through the diode connected to the GRN/WHT wire which is indirectly connected to ground through the 4 relay coils and brake light filaments AND the high mounted brake light LED strip. The high mounted brake light is probably the more significant component in the ground connection. Remove the high mount brake light and you lose that ground path causing permanent illumination of the indicator. You are not the first person to discover this problem after removing their high mount brake light.

As a test, try reconnecting your original high mount brake light and switching the ignition key to run. If the safety indicator stops illuminating then that confirms that the safety indicator is working properly and it is not the monitoring circuit that is failing. It should be possible to spoof the circuit so that it does not continuously illuminate. You need to add in a combination of LEDs or a diode and resistor that emulates the high mount brake light. Something like 4 or 5 white LEDs with a forward voltage in the 3.5 volts range connected in series might work. The combined voltage of the diodes has to match the typical operating voltage in the car which is usually around 14 - 14.2 volts. If you can measure the steady state current draw of the high mount LED strip at 12 volts, you may be able to replace the strip with a single diode like a 1n4001 and a resistor. The resistor would have to have a resistance equal to:

R = 10.9volts/(current in amps)
 

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Oh wait, maybe Old Guy is saying that won't fix your issue.

Nevermind....

If you mean connecting the ORG/WHT wire to ground, that will fix the issue of having the brake failure indicator illuminating all the time. However, it does that by completely by-passing the brake light failure sensors so you will never get an indication of a failed brake light. It is the electrical equivalent of applying a piece of tape over the brake failure indicator light.
 
Thank you for the concern and letting me know about the possible fire hazard! Luckily the Brake Lamp indicator on the dash comes on internmittently at times. Sometimes when the ignition on was initiated and the other times it is off until i eventually notice it while driving. It seems the general consensus is to reconnect the OEM 3rd brake light and see what happens. Tomorrow ill try it out and let you guys know!
This is a little suspicious. Please check if the "BRAKE LAMP" indicator comes on directly after ignition on (or/and together with the indicator for hand brake applied even though it's released).
You could be observing the first indications of capacitor failure at the cluster - this is a serious issue that can be a cause for a fire and should not be treated lightly.

To rule that out for now you could re-attach the 3rd brake light temporarily and see if the warning goes away - it might simply be a burned out bulb or corrosion at the bulb holder :)
 
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After the bulb check mode when you first turned the IGSW On, the 'BRAKE LAMP' warning light should be triggered only after you applied the brake pedal.

This is the JDM/Acura bulb failure detection circuit using the reed switch concept.
The coil is only powered up when the brake pedal was operated AND all the brake light bulb filaments were fine to create the closed short circuit to the GND.

Therefore, it can't detect the failure without applying the brake pedal first.


If the warning light stayed On after the initial bulb check mode even before touching the brake pedal or being triggered at random timing without applying the brake, it's most likely the first sign of the gauge cluster failure.

On some cases, the warning light behaved the other way round.
It stayed Off even after on purposely removing the brake light bulb and applied the brake.
This is very rare case compared to the above false brake lamp warning light but one thing to remember.



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After the 1st sign, it tends to disappear for quite some time so the owners thought it fixed itself somehow.

Then, you start to see other warning lights in that LED panel such as the door ajar indicator, etc.
It tends to happen when the humidity is high inside the cabin.



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All NSX will sooner or later suffer from the leaky capacitor issue and it's just a matter of when and not if.

Hard to predict when it will start leaking because there are some without a single leakage even after more than 20 years whereas many started at much earlier stage.

Temperature is the key factor so if you live in warm/hot climate, garaged in fairly mild environment or tend to keep the cabin warm/hot while driving, better take a look.


One of the reason why I don't recommend using the tape method covering the warning light as you will miss the 1st sign of the failure that could lead to the small cabin fire....


Kaz
 
If you mean connecting the ORG/WHT wire to ground, that will fix the issue of having the brake failure indicator illuminating all the time. However, it does that by completely by-passing the brake light failure sensors so you will never get an indication of a failed brake light.

Uh, yeah, that’s why I started my post “It's really easy to bypass the brake-light-out warning.”

It’s certainly a compromise, but I chose upgrading to brighter and more reliable LEDs, realizing I would have to disable the bulb-out warning.

Not really worried about my LEDs failing, although admittedly it can happen.


 
Which LED 2057 bulbs are you guys using that are brighter and also produces the 2 stage brightness when pressing the brake?

Any 1157/2057 LED should work. I had several different ones I had bought for other cars, not sure which I ended up putting in my NSX.

Be sure to get red LEDs for tail/brake light use.

Mine came from one of these two sources:

https://www.diodedynamics.com/led-bulbs/tail-and-turn-signal/1156-and-1157.html

https://www.superbrightleds.com/cat/car-boat-light-bulbs/filter/Stock_Bulb_Number,1157,197,8888:

You can convert turn signals too, but have to either add resistors (so they use more power and the car thinks they are normal bulbs) or modify the turn signal flasher- that's what I did. There's a thread on that I can find if that would be helpful.
 
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