Brake sensor on front pads - light is on

[philmeister]

All, I am looking for an answer here before I leave from work today and start working on my car tonight. (GTI/VR6/2000) Thanks in advance.

Problem: We had some big floods here in NH last week. I drove thru a 8" deep puddle on my way home one day. Immediately, the brake sensor light came on and did not go off. I ignored it, thinking it would dry out and go off. It did not, and a week later it is still on. Of course, I kept ignoring it, thinking I would have to reset the code or something, and that there was no problem. Anyways, today, the brake pad on the front drivers side gave out, to my surprise. The passenger side is in fine condition - only 1/2 worn. This leads me to believe the caliper or piston is getting seized. I will take apart tonight and put new pads on and lube the caliper pins well.

Question: What exactly does the brake pad sensor sense? How does it work, anyone know? Why would it have turned the "check" brake light on when I went thru that puddle, and then not turned itself off after drying out?
Thanks,
Phil

[clove911]

if your wearing your drivers side pad down faster than you might have a sticky caliper. The sensor does sense when the pad is low, so if your pad is low, like you said, thats why it came on.

[philmeister]

So, in case anyone is interested, the brake pad sensor works as follows:

The sensor has a wire that goes into, and then back out of, the pad. It is embedded in the wear portion of the brake pad. As the pad wears down, eventually the wire becomes exposed and gets worn thru (i.e. broken) from pad wear. This opens the electrical circuit, and turns on the brake pad sensor light on the dash. The wire gets broken when there is approx 3/16" of pad left (quite a lot in my book). Only the driver’s side has the sensor on it, so it is really VWs way of telling you to look at the pads. Kinda silly really, since the rear pads normally wear out long before front pads on the Golf's.

New set of front, sensor equipped brake pads are $80.00 at the dealer (I didn’t have time to buy from germanautoparts.com). That’s pretty expensive, but they do have an enormous amount of pad thickness when new. My front pads lasted 150,000 miles, but that's really an indication of how much highway driving I do.

[s18t]

i have my brake pad sensor and abs light on but thats cuz both wire are broken. they sell brake pads at auto-zone, advance or orilleys that fit out calipers. i didnt pay more then 50 bucks for both fronts.