Whirlpool Gold Dishwasher Detergent Latch

Detergent latch will not close and is stiff when attempting to close. Listed part assembly does not look like unit installed.
Must the assembly be replaced and how does one access to remove and replace? Is there a smaller subassembly that will correct the problem?
Would appreciate access informtion to remove and replace as well as confirmation of the part with the correct part number.
Thanks in advance.

Yes it is replaced as an assembly.. Remove the 4 screws on the lower right and left sides front lower cover lifts off to service the dispenser