How to Diagnose Your Mercedes Benz 300SE Window Regulator Problems
One of the hardest problems to deal with when you have a failing window regulator is that you won't be able to pass an inspection. Based on Mercedes Benz 300SE recall reports, window regulator failure for this model is fairly common. There are owners who claim that the passenger side window regulator fails first, followed by the driver's side and the rear window regulators. If you don't take care of these problems the first time you recognize it's slipping, you might find yourself in a more difficult position later on. Here are a few tips on how to diagnose your window regulator's common problems:
Window getting stuck halfway
A window that gets stuck halfway or does not fully open or close might not automatically have a defective regulator. Instead, there might be a problem with the regulator itself being stuck. Check if it is well-lubricated. Troubleshooting this kind of problem will require you to take the door panel off. Although this is a job that requires time and effort, it must be done to allow you to inspect the amount of damage done to the regulator. Lubricate the regulator's brackets with some lithium grease or WD-40 and see if this solves the problem.
Window moving slowly when the switch is pressed
Once again, the door panel needs to be removed for you to be able to see inside it. Look for the window regulator and this time, check if the brackets are filled with dirt. Even if the regulator is well-lubricated, dirt and grime can limit its motion, which can cause the window to move very slowly even when you press and hold the switch down. Simply cleaning it and putting everything back together can solve the problem.
Windows not opening at all
If one of the windows won't open at all, check if the fuse is blown. It is sized just enough to be able to open all four windows at the same time. If you push the switch and the motor produces a whirring sound, it could mean that the regulator is bad. However, if the motor doesn't even make a sound at all and the window doesn't move, the fuse might be blown. Old age can pop a fuse, so check if it has given up on you.