Brake lights - only when starting with handbrake engaged

[asylum]

Dear All,
Since I had my last TB job with the motor out, sometimes when I start my car (91, MT) with the hand brake engaged, I get the 2 red brake lights on. If I drive, then I get ALB and TCS. If I start my car without the hand brake engaged this never happens and no lights coming when driving or engaging the hand brake.
I pulled a code (do not remember the number) that highlights "hand brake switch" or something like this in the manual.
One remark : my handbrake is very tight. Seems to engage as soon I pull it. If this has a relation.
Any idea of the reason ?

 

[Old Guy]

I get the 2 red brake lights on.

I am going to assume that those two lights are the Brake System Warning light and the ABS indicator light on the dash cluster. The only things that can turn the Brake System Warning Light on are the Parking Brake Switch and the Brake Fluid Level Switch. That circuit is dumb-ass simple. You said

no lights coming when driving or engaging the hand brake.

If that means when you are driving you apply the hand / parking brake and the Brake System Warning Light does not come on, then that suggests that you have a problem of some kind with the Parking Brake Switch being sometimes on and sometimes off. The problem could be the switch itself, the wiring or the adjustment of the handbrake. Based upon your description of the hand brake being tight, I think it might be appropriate to adjust the hand brake first (the switch does not appear to be adjustable). The service manual provides a diagram of the Parking Brake system on page 19-27; but, no guidance on proper adjustment. There is an adjusting nut at the equalizer where the cables attach to the brake lever rod. I assume the procedure is adjust the lever to get the lever movement that you like and confirm that the parking brake switch is operating correctly when the brake is engaged. Make doubly sure that the rear calipers are not dragging when you release the parking brake.

Of course, make sure that your Brakes System Warning light is not coming on because the brake fluid has dropped to the level where the brake fluid switch may bouncing on and off as you drive.

The parking brake switch provides an input to the ALB controller. The ALB controller will generate a code 2 error if the parking brake switch (or the brake fluid level switch) stays on for 30 seconds or more after you start driving. So, I think the likely cause of your problem is that your parking brake switch is doing flakey things. That might be a switch problem or it might be a problem with the adjustment of the parking brake mechanism.

A parking brake switch problem will also cause TCS problems (again error code 2)

I underlined the 30 seconds part because the parking brake switch needs to stay on for 30 seconds while driving to cause the ABS warning light to come on. Briefly applying the parking brake while driving will not cause the ABS warning light to illuminate.

 

[asylum]

Thanks for the answer. I was not clear. The parking brake light works perfect. Light on when parking brake pulled, light off when parking brake released. Just this thing that sometimes the two red brake lights come on when starting the car with parking brake pulled.

Well, I will try too look to the switch, its wiring and the adjustment.

 

[Kaz-kzukNA1]

@asylum What's the year model and country code of your NSX? KF, KG or something else?

Kaz

 

[Old Guy]

If you used the service check connector to retrieve error codes and the ALB and TCS are showing error code 2 'Parking Brake', then the ALB and TCS are getting a 'brake on' message. That could be caused by the actual parking brake switch of a shorted wire some place or in the worst case a defective controller. If both the ALB and TCS show error code 2, then it is unlikely to be a controller problem.

All of this is based upon the North American service manual. Non North American cars may have different features.

 

[asylum]

Yeah both get a parking brake code. So will check the switch.

91 Swiss car.

 

[Old Guy]

Both the ALB and the TCS getting a #2 code at the same time does point a finger at the parking brake switch circuit. When checking the switch, if the switch is not the obvious problem, keep in mind that a short circuit to ground on the switch circuit will look like the switch has operated so examine the wiring for damage. This would include the wiring out to the float switch on the brake reservoir which is all part of the same circuit.