Rear brake lights are not working - CLK Mercedes-Benz Cars & Trucks

Hi,

There are a couple of probable reasons why the brake light are not working, they are:

• brake switch - underneath the dash. It is activated when the brake pedal is pushed. It is a spring loaded switch and is normally off. If the sprin is defective/missing then the switch will not activate;
• brake light fuse;
• bulbs;
• corroded bulb socket - most brake lights are integrated with the rear park lights. The bulb socket would have 2 contacts, try checking if they are clean and reaches the mate in the end of the bulb;
• wrong installation - the bayonet socket of most park/brake lights combo are offset, there is a right and wrong way if installing it into the bulb socket;
• loose wire - it would be required to trace the brake wire to where it joins the rear harness;
• loose ground - same as above or a workaround is to wire an additional ground wire from the housing of the bulb socket to any screw that is connected to the body ground.

Check if the bulb is working,if its good to go,check the fuse