I have a 2003 mazda b2300 (same as a ranger) and I had a guy the other day tell me I had no brake lights. I got a new switch and put it in but I noticed a black plastic bushing leftover.
I tested the brake lights and the lights worked.
I took it all back apart and put the bushing in and no brake lights. after about 2 hours of head scratching I gave up and left the bushing out.
Stumped on this one....... Any ideas???

 

Maybe the bushing is required for some vehicles but not for others.