I have a tough time training triceps because a few months ago, my elbows would hurt a lot after increasing the weight. I tried training triceps with very light weight and would avoid full lockout (which caused the most pain). Now I've hit a brick wall - I'm stuck at a fairly light weight (20 reps+) and whenever I increase, my elbows start hurting regardless if I avoid lockout. This happens when doing rope pulldowns and lying barbell extensions.
After training, I ice and elevate my elbows if necessary which usually makes the pain subside after a few hours.
Any ideas how to heal this injury? I've stuck with light weight/careful form for a 8 or 9 weeks already. It's noticeably improved, but will more rest necessarily help?
EDIT: added diagram