New owner with problems

[StephenVA]

Below is the Wear Sensor that turns on the light "Brake Linings". Your 2005 3.0 X5 has two sensors one left front and one Right rear. They are a "One Time Use" sensor that trip the light when the min thickness of the pad is reached at the caliper in which they reside. They operate just like the noise sensors that most manufacturers use on bake pads installed in US cars. When min thickness is reached, they do something. In the case of the noise sensors, they scratch on the rotor face and create a hi pitched noise. The BMW wear sensors are nothing more than a low voltage wire circuit that when broken (cut by the rotor when min level of the pad is reached) turns on an idiot light on your dash.

When you replace the pads, you replace the sensor, turn on the key (don't start the car) for 30 secs and the light is reset. All shops replace these sensors each and every time brake system is serviced. DIY efforts allow you to reuse the sensor IF it has not been activated, i.e cut by the rotor. Note:70/80% of brake wear is on the front pads. So you get the chance to do the fronts twice to every rear pad replacement.

Recommendations: Replace the pads all the way around on your first brake job of ownership, that way you will know what brand is used, everything is in working order, and if you choose, you can purchase pads that will give you either OE braking dust or something a whole lot less dust.
Calipers - My personal recommendation is to replace all the little parts on the calipers like mounting pins, the rubber boots in the calipers, and flush the brake fluid as this will give you a great base point and peace of mind when you pound on the brakes one morning trying to avoid another sleepy head on their way to work.
Pads - POWER STOP 17681 Z17 EVOLUTION PLUS w/Hardware Kits, as these will give you close to OE cold stopping, better hot stopping, and will have 20% of the dust. See Rockauto.com.
Brake Fluid - See Autozone/Advance/Wall Mart etc and pick up DOT 3/DOT 4 silicone brake fluid like Valvoline brand. Flush every two years and you are good to go.

I am sure others will chip in with personal favorites as well.. Once it warms up, change the oil and filters (air, Oil, and cabin) as well as that is the life blood of the vehicle. Lots of self help info post up top under "Articles", so you get to experience replacing the valve cover gaskets & seals, Alt bracket oil seal, cooling system refresh (Rad, pump, hoses, sensors, clamps), change Diff fluids, CCVC refresh (OIL SEPARATOR), wiper blades, tires, and all the normal wear items that will need service in the life of our vehicles. Welcome to the family. This site has a TON of information so make the SEARCH feature your first choice before posting as trust us, you are NOT the first one who is experiencing the issue.