If the drawer is open, is the latch still stiff to operate? Try lubing the mechanism. If this difficulty is only when the drawer is closed, it might be that the latch is too tight and creating friction in the mechanism. You could try adjusting the gap that the drawer latch closes on. Be warned, it might cause the drawer to rattle when driving. If so, a small 'bumper' or pad might be needed for the drawer to close against.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI