If your little guy is eating lots of vegetables, greens, etc, that is good and he is probably getting everything he needs in his diet with the variety of vegetables. Shhhh.....don't tell him but if he likes peppers, he is eating....berries!
To help broaden his diet to include fruits, you may wish to eat pieces or slices of fruit in front of him..widen your eyes, chomp the fruit, chew it with your mouth open so he can see...make yummy sounds....and act like this piece of fruit is just the most wonderful, marvellous food item in the entire universe! He may become curious about what you are eating and show interest in tasting the fruit (such as by leaning toward you, and/or intently watching you eat the fruit). If he does, offer him a piece (not one you have bitten from - a fresh piece) and let him taste it.
You may want to start out with slices from a couple of different kinds of apples. Eclectus tend to have preferences in apple varieties, and if you have slices from a couple of different kinds, you may find he prefers one type over another...such as Granny Smith, Red Delicious, HoneyCrisp...our pair really like HoneyCrisp apples but are not very interested in any other kind. Others like the tart green ones (like the Granny Smith), etc.
You may also find that your Eclectus likes fruits that are just a little bit under ripe to human taste....try kiwi fruit that you personally would wait a day or two to eat. If your Eclectus will not eat ripe papaya, try green papaya.
Figs are a fruit Eclectus like ripe, with lots of nice seeds inside. If you offer figs with undeveloped seeds inside, your bird may not want it.
You can also "hide" fruit in his cooked mix or bird bread by adding diced apples, pears, chopped cranberries, whole or chopped blueberries, applesauce, etc.
But if he is eating his vegetables well - peppers, carrots, greens, etc - then I would not worry..just be patient and tempt your Eclectus with fruit from time to time and let him become curious and interested on his own.
We hope this information is of help to you.
Al and Mary
Cabby and Chardy (SIE)