Brake pad sensor question
 

How much pad is left when this sensor triggers? I'm pretty close to the backing plate but no warning light yet. Making me a bit uneasy to be honest. Starting to wonder if the sensors were reused or never installed on the last brake job by the dealer. Will the dealer only replace the rotors and pads if the warning light is triggered?

The sensor will work. Once the sensor is triggered you still have a few hundred miles of driving to go. But it's time to get them replace. I prefer to do it before the sensor is triggered so that I can reuse the sensor. Once it's activate ita dead and you need to replace it. It's cheap.

I'm still under warranty.. Reason for asking. Have heard the dealer will not replace unless the brake pad lining light is on..

You'll get a light if the pad sensor wasn't installed, unless they bypassed it. It's basically a little sensor that sits within the edge of the pad and has a looped wire inside of it. When the pad wears down, the sensor comes in contact with the rotor and wears away the plastic, exposing and breaking that wire, which in turn triggers your warning. The only downside with this system is if you have uneven brake wear as the sensor is only on one side, not both. Local places like Les Schwab, Discount Tire, etc will do free brake inspections, so take it there sometime, let them go through their paces by trying to sell you everything under the stars, say thanks and walk out with the information knowing how your brakes are doing. If in fact you've got uneven brake wear, a set of pads is like $80 and can be done within a few hours if you read the DIY's on here with basic hand tools.

Mine triggered several months ago. I have been checking it every month and the pads are still at 4-5mm even 3 months and 3K miles later. So at least in my case the sensor came on way before the brakes needed to be changed. Minimum spec per the service manual is 3mm. When I get to 3-4mm I will replace them. I bought all the parts several months ago, but why replace early? I did rotors this time because they looked pretty trashed and off and on have had some chatter. Plus I found some nice Brembo rotors for $100 each.