V36 Park Brake Light stays on

[West]

Hey guys

The V36 park brake light has been on and won't go away recently. I have top up the brake fluids, check the park brake switch and everything seems fine. I could replace the switch but before i do that, is there anything else that i need to look at first?

This is what's said in the 2009 G37 Sedan manual .....
 

 

Quote

 

Brake warning

light

This light functions for both the parking brake

and the foot brake systems.

Parking brake indicator :

When the ignition switch is in the ON position,

the light comes on when the parking brake is

applied.

Low brake fluid warning light :

When the ignition switch is in the ON position,

the light warns of a low brake fluid level. If the

light comes on while the engine is running with

the parking brake not applied, stop the vehicle

and perform the following:

1. Check the brake fluid level. Add brake

fluid as necessary. (See “BRAKE AND

CLUTCH FLUID” in the “8. Maintenance

and do-it-yourself” section.)

2. If the brake fluid level is correct, have the

warning system checked by an INFINITI

dealer.

 

 

Thanks

[The Max]

Unplug the sensor cable on the brake fluid reservoir and see if it goes away or not. If doesn't go away, it is not the fluid level switch.

How did you test the parking brake switch?

Edited September 12, 2020 by The Max

[West]

9 minutes ago, The Max said:

Unplug the sensor cable on the brake fluid reservoir and see if it goes away or not. If doesn't go away, it is not the fluid level switch.

How did you test the parking brake switch?

Will try the brake fluid reservoir sensor cable tomorrow, thanks.
I tested the park brake switch by using my hand to press the "thing" in, have not tried to unplug or with a current tester yet.

Thank you

[West]

On 9/12/2020 at 7:03 PM, The Max said:

Unplug the sensor cable on the brake fluid reservoir and see if it goes away or not. If doesn't go away, it is not the fluid level switch.

How did you test the parking brake switch?

have unplug both, no go, i'm leaning toward parkbrake switch

[The Max]

Interesting. The parking brake switch only makes contact to ground when the lever is actuated in the engaged position. Likewise, the fluid sensor is meant to only make contact to ground when the fluid is low.

So by disconnecting both (I assume they were both disconnected at the same time), they're open circuit. If the parking brake light in your dash didn't go out, there's likely to be something else wrong.

[West]

19 hours ago, The Max said:

Interesting. The parking brake switch only makes contact to ground when the lever is actuated in the engaged position. Likewise, the fluid sensor is meant to only make contact to ground when the fluid is low.

So by disconnecting both (I assume they were both disconnected at the same time), they're open circuit. If the parking brake light in your dash didn't go out, there's likely to be something else wrong.

I have a feeling they are closed circuit, i will bridge the circuit at the plug today and see if i am right, at the same time, have ordered a new switch from Nissan.

[West]

On 9/14/2020 at 2:14 PM, The Max said:

Interesting. The parking brake switch only makes contact to ground when the lever is actuated in the engaged position. Likewise, the fluid sensor is meant to only make contact to ground when the fluid is low.

So by disconnecting both (I assume they were both disconnected at the same time), they're open circuit. If the parking brake light in your dash didn't go out, there's likely to be something else wrong.

Found the culprit, 
Passenger side sunroof drain plug is clogged, water pool up under passenger foot-well, there is a small ECU there, not sure what it's for, unplug it (it was wet like a rat) and light goes away, voila!!!

Just gotta dry it up and plug it back in again.

 

[The Max]

Ouch dude. The little control unit behind the kick panel? If that is the location, that's your BCU. You definitely want that guy to be well-protected before you have more than just an annoying parking brake light stuck.

My severe hatred for the sunroof is once again vindicated.

[West]

7 hours ago, The Max said:

Ouch dude. The little control unit behind the kick panel? If that is the location, that's your BCU. You definitely want that guy to be well-protected before you have more than just an annoying parking brake light stuck.

My severe hatred for the sunroof is once again vindicated.

There is a control box, or ECU, under the carpet where the passenger feet is.

I kid you not, its a combination of things......

I clean out the sunroof drain, then it's wet again. I found that somehow, water seep in where the cabin filter is. Checked the rain cowl/tray thing, found a design flaw, well it was good when it's brand new but overtime, it became a design flaw.

From the rain cowl/tray, i found more design flaw, no wonder these cars are well known to have water coming in issues, very common with the g37 crews in the US.