master cylinder harness

[unclebubbaSE]

Hey everyone, don't like to repeat posts, but I couldn't find anything specific about my issue...I found the harness that plugs into the brake master cylinder to be disconnected, just hanging below. When I plugged the harness connector back into the master cylinder, the "brake" light on the cluster will come on and stay on solid after engine starts and while driving. It of course will usually go out when the e-brake is released, but now will not. I guess I know now why it was disconnected!. Is this the abs harness, or a level sensor harness?. Why would the light be on when plugged in as normal?.

The brake fluid is at proper level, and the light went off when I re-disconnected it.

Thanks in advance for any thoughts, info!.

[SkiBonne]

If that light goes on with the sensor connected, there is usually a problem. If there is no other issue with the brakes, there could be an problem with the sensor itself. How does the vehicle brake? Does it stop normally?

[nos4blood70]

That is a level sensor. Might be a bad sensor, hence why someone unplugged it in the past.

[haro1225]

That would be the fluid level sensor. Shouldn't have anything to do with the abs. Just keep an eye on the fluid to make sure there is enough in there.

EDIT: what Carl said ^^

[harofreak00]

There is a problem with the sensor. Someone disconnected the wiring so it doesn't display the BRAKE light all the time. The sensor itself is really cheap brand new, like $10. Try replacing it first. If that doesn't fix it, you'll need to remove the reservoir and clean it out. There is buildup inside that causes the float not to move. (The actual sensor doesn't even touch the fluid) In my experience, you'll likely run into the dirty reservoir before the bad sensor.

[unclebubbaSE]

Yea, the vehicle brakes perfectly, no worries there. If it is a bad level sensor itself, would I have to remove the master cyl. assy. to replace it?....if that's the case, I'll leave the sensor harness unplugged and check the fluid level regularly, rather than have to remove the freakin' master cylinder just to get things "proper"!.

Thanks for the feedback guys!
Cheers

[harofreak00]

No, the sensor is very easy to replace, it just pulls straight out. See video: https://www.youtube.com/watch?v=RqHETudnbNo

[unclebubbaSE]

Great video link...I can't believe it would be that easy. I'll order mine today from rock auto for $3.48 plus shipping!.

[unclebubbaSE]

Well...I replaced the fluid level sensor in the master cyl. today, reconnected the harness and the *dang* light is still on!.
Brake fluid was strange color, almost a dark "moss" green, as opposed the the usual darker brown color. I'm probably going to have brake flush performed just to get fresh dot 3 in there and see what happens. If the flush doesn't solve the problem, I'm just going to unplug the freakin' harness and forget about it.

The car brakes fine, that's all I'm concerned with at this point.
Cheers!.

[harofreak00]

If you have a shop do the flush, you'll have to specifically ask for the reservoir to be cleaned out. They will need to remove it from the master cylinder (a couple pins that pull out) and then use some cleaning solvent inside the reservoir and slosh it around.