I just finished adding a brake light on my 01 220. It's pretty easy to do the work but I had a hard time finding some of the parts.
You need 1 or 2 hyd. brake switches a double polarity light soket ,some wire, connectors and a 1157 LED bulb. Tap in to the wir for your rear parking light (I think its red) send the current to your switch(es). From the switch add a wire back to the brake side of the double polarity soket, instal the bulb and it should work.
You will probably need to turn the reservoir around on your rear master cylinder because of the hyd. switch and weld on a tab to your protector. If you just use a regular 1157 bulb in the back, your headlight might dim when you press the brakes.
It's all pretty easy to do, Good luck