Brake pad sensor .... which one? '91 300E
 

Anyone know a good way to check which sensor is illuminating the dash light? I can see through the wheel slots that both pads are good.

Pull the wheels and check to see if any are grounding out.

It could be an inner pad is worn.

IT could be the way the sensor wires are routed, or it could just be loose.

The sensor has to make a ground contact to light up the gauge cluster light.

You might have rear sensors, some cars do. Check those to if you got em.

If you need pads, order em for partsshop/fastlane on this site.

Alon

Brake pad sensor .... which one? '91 300E
 

I found it was the right front sensor that was bad. Since each brake pad has a hole in which that sensor can be inserted, I inserted it into the outboard pad. It seems it is much easier to crush the sensor when installed on this pad. I put the new sensor on the inboard pad and everything is fine. Light went out.

The inners will always wear faster than the outers. That is the pad you want the sensor on.

Oh good, then I did relocate to the correct pad. Do the inners wear faster because of less air flow?

Just a guess but I think its because the inners have the pistons behind them.