Fast Car

1. Drive the 325is to your garage or a parking lot. Turn the fan on and feel for any air coming out the vents. If there is no air, then the blower motor needs to be replaced. Put the 325is into Park, then engage the parking brake so there is no danger of gear slippage during the repair. Make sure you have room to maneuver around the front of the BMW for the removal process. Turn the BMW off and open the hood and trunk.
2. Go into the trunk of the BMW and disconnect the negative battery cable from the cars battery. The battery is located in the trunk of the 325is for better weight allocation. Go around to the front of the 325is and prop the hood up with the hood prop stick. The blower motor assembly will be mounted with six screws against the rear firewall. Remove the screws with a Phillips-head screwdriver and pull the blow motor assembly off the firewall.
3. Press the pressure clips on either side of the motor and pull the motor from the blower assembly. If the blower motor has burnt out, then there will be a smell of ozone in the air. If the fan has broken, then some of the blades will be snapped off. In either case the blower needs to be replaced. Disconnect the power wire from the rear of the motor and then connect the power wire to a new blower motor.
4. Slide the blower motor into the blower assembly until you hear the clips click. Then screw the assembly back on the firewall. Tighten all the screws down by hand, as high-torque power drivers could crack the assembly. Close the hood and then go around to the trunk to reconnect the negative battery cable. Close the trunk and then turn the BMW 325is on. Turn the fan up and feel for any air. If there is no air flowing, then the power cord was not plugged in flush. Take the blower motor out and reseat the power cord.

1. Check the connection speed sensors located on each wheel hub. Locate them by following any wiring coming out of the wheel hub and following it until youve found the sensor. Check if the sensor is dirty or if its wiring has frayed or become disconnected somehow.
2. Check the brake components of your BMW by inspecting the rotors and brake pads that are on each corner of the car. If the pads are unevenly worn, your rotors are worn down (indicated by scratch-like marks on the surface of the rotor), or if the brakes are not functioning as well as they normally do, the DSC could be malfunctioning due to an issue with the braking system.
3. Check the adjustment sensors such as the steering angle sensor, lateral acceleration sensor, and pressure sensor by bringing the BMW to a licensed mechanic or BMW dealership. Using electronic diagnostic equipment, they can run tests on your DSC system to determine if any of the three aforementioned sensors are failing, and thus causing the issues with DSC.

1. Inspect the paintwork for damage. Scratches, dents and corrosion can all be indicative of greater damage elsewhere. Any scratch on the paint can be expensive, because Mercedes often used limited run paints (restricted to certain cars and years of manufacture). Paint needs to be repaired soon, as it can lead to early rust. Any dents in the body panel could mean that the Mercedes was in an accident and could have frame damage underneath. If there is corrosion in the panel then it is guaranteed that there is rust elsewhere, especially on the undercarriage.
2. Open the hood and inspect the engine. There should be no debris in the engine bay or radiator. If your Mercedes is a carbureted model, then inspect the barrel intakes for damage to the valves. Damaged carburetor valves can lead to irregular air-fuel mixes that can damage your piston or sleeves. If your engine is fuel injected, then inspect the fuel lines for leaks (pay special attention to the rubber hoses, as they have a tendency to become brittle with age). Inspect the power lines on the hybrid model for any damage (do not touch damaged ones). Call a Mercedes dealership to repair a hybrid model.
3. Turn the car on and listen to it idle. The hybrid Mercedes should not run the engine while the car is sitting still, only when under power. Non-hybrids should idle around 2000 rpm (if it idles higher than this, there may be a problem with the fuel-air mix). Watch the engine temperature. Even on a hot day, the engine should remain cool in idle.
4. Drive the Mercedes forward and listen for the engine. AMG models should roar when the throttle is pushed in, even at sedate speeds. Non-AMG models should be whisper quiet, even at highway speeds (if you hear the engine, then some of the noise isolation material has fallen off). Mercedes prides itself on providing quiet interiors on their regular cars. The car should easily absorb any bumps in the road. If the car rocks a lot then the shocks may be shot.