"Brake Fluid" light, Check my thinking please?

I have a 2000 C2 and the "Brake Fluid" dash warning light is on, I think the issue is the sensor in the reservoir, but I do not know this circuit, so was wondering if I could get someone to check my troubleshooting. The system should be good: the brake fluid is full (~1 mm below the Max mark on the reservoir), there aren't any leaks, and system was just bled (with a Motive power bleeder). I can't say whether the warning light is new or not, because I've never had the car started until this weekend. I'm working from an unknown baseline. I dug through the Bentley and scoured the wiring diagram. The wiring diagram (EWD-14, sheet 3-1999) suggests that this is a simple on off switch with one side (BR wire) connecting to ground point 4 under the dash, and the other to the instrument cluster on plug I, pin 4 with a VI/RE wire. I believe the icon is a normally open single pole, single throw switch. I probed the connections with a multimeter. The harness connector has two female pins, that do not have continuity (unplugged from the sensor). The sensor has two male pins, and measuring across the pins, shows continuity. If I leave the sensor unplugged (so no continuity on the circuit), the dash light is off. If I jump the pins in the connector (used a 3 amp mini-fuse, since it was just the right size), to close the circuit, the dash light is on. Based on all of this, I think the brake fluid sensor is a normally open switch that gets closed when the fluid level gets too low. This switch may have failed in a closed position, making the car think the brake fluid is low. My conclusion: failed or inoperable sensor. R&R it. Agree, disagree, have different thoughts?

Makes sense. The wiring diagram also shows the brake fluid level switch is Normal Open, which also supports your theory.

sounds legit to me.

Thank you both. I have a replacement reservoir with a sensor on it's way. I'll report back once I install it.

On two occasions now - both during high-speed, fairly-high-G mountain driving - my brake fluid light has illuminated despite the reservoir being full. Both cleared after restarting. There was a year or more - and at least one brake fluid flush - between the two events. In both cases, I was driving the car hard enough that the light's appearance was worrisome, but roadside checks of the fluid level were normal. Weird, and more than a little unsettling. I may replace the reservoir...never having that happen again would be nice. OP, looking forward to your results.

5CHN3LL - that exact issue came up in a lot of threads when I searched around on the topic. Especially in driving events, racing and mountain/canyon carving. The circuit is pretty simple, and I could see how it might happen. I'm guessing it doesn't have any intelligence in the circuit. I don't suspect a new one would help. Someone should whip up a "smarter" circuit that requires the fault to be present for longer before allowing the light to come on. Maybe an aftermarket product opportunity for an EE in the community? It wouldn't be a very complex thing, and could easily be plugged in between the sensor and the harness connector. Maybe as simple as requiring a open circuit for some time period (10 seconds?) before opening the circuit to the fault light.

Would be very easy if this is the issue. Would just need to install a relay with a pickup delay (how ever many seconds you think 2s). Circuit would function the same as the switch but would need the switch to be closed for x # of seconds prior to the relay contacts closing. I would assume a 12v relay with pickup delay of 2s (or adjustable) with 12v 1a rated contacts would be plenty. Then just get some plugs and bam.. plug and play fix. Amazon Amazon

As caretaker of a 21-year-old Corvette and a 19-year-old 911...the one thing I do not find myself wishing for is MORE electrical components to troubleshoot. As far as requiring a delay of X ms before triggering the low fluid warning: this would also serve to filter out early warnings in a legitimate low-fluid situation where the fluid level is low enough to trigger the light when sloshing but still sufficiently full to do the job. I'm not sure that this possible loss of sensitivity justifies a "fix" that is mostly a band-aid to avoid replacing what seems like a semi-failure-prone sensor. I like the underlying thinking, but I don't like the idea of making things even more complicated. At least we know that the low fluid warning light has two possible causes now...and the troubleshooting flowchart is about my speed.

Interesting. I recently started a similar thread on this. Although I titled it "looking for a durametric cable" since I thought my "Brake fluid low" warning was triggered by air in the ABS system. Sadly I wasn't paying enough attention and let the brake reservoir run dry when flushing brake fluid in the summer. https://rennlist.com/forums/rennlist...ake-bleed.html I hadn't searched for a wiring diagram though and had assumed there was potentially another fluid sensor in the ABS pump. If there is only one sensor that triggers that warning light than I'm in the same boat as everyone here I was able to get the light to trigger by driving aggressively in the rain (as well as on the track) but in hindsight that could have been due to the fluid swishing around.

Love the self portrait 5CHN3LL ^^

Perfectly sound logic. I wonder if the sensor is mechanical (IE a float) or capacitive. If its a float style sensor it makes sense that aggressive cornering on a slight tilt could potentially 'lift' it up causing a false alarm. Maybe you need stiffer suspension