The 400 level sections are located at the very front of the View Level at Angels Stadium, which is the upper deck at the ballpark. As these seats are furthest towards the field on the upper deck (where overhangs are not available), some of these seats may see a good amount of sun.
Specifically, the 400 level sections down the first base line and near the right field corner will see the most sun of any section on the View Level as they face towards the West and will have the sun in the face for most of the game. 400 level seats on the third base side will have relief from the sun quicker as you face east with your back to the west, and these seats will also have a better head on view of the scoreboard in right field.
The best seats for finding the shade at Angel Stadium are located in Sections 205-213 down the third base line, as these will have the sun at their back sooner (seats face east), and are also well protected by the overhanging upper deck just above. Look for seats near the front of these sections, as some of the further back rows will have a more limited view due to the overhang.