The timer knob simply pulls off the shaft with a solid, steady pull. Cleaned the timer cavity of lint/dust buildup. Aligned the keying flat of the shaft and knob and pushed the new knob on with careful, steady pressure until it was obviously seated. No tools required other than a vacuum.
The door switch would sometimes not shut the dryer off when the door was opened. New switch came with new fast-on connectors. Replacement required opening the top cover of the dryer and hinging it up. This is easy to do. There are 2 spring tabs that secure the front of the top cover to the dryer body. Using a thin putty knife, push each tab straight away from you while prying upward. The front of the cover will slightly 'pop up' at each tab location. Simply lift and hinge the cover upward to its resting position. Locate the door switch and note which wires go where. They are different colors. Simply pull them off the switch terminals. If the connectors show signs of overheating, replace them. Cut the wires as close as possible to the existing connector. Carefully strip about 3/8" insulation from the wires. Hold the barrel section of the new terminal with strong pliers, insert the wire into the crimp barrel and squeeze hard! Pull-test to ensure the crimps are solid. Note the orientation of the switch plunger to the switch body. It is offset to the left. The new switch should be installed likewise. Squeeze the lock tabs of the switch and push it out. Simply push in the new switch with the plunger to the left and carefully slide the wire terminals onto the switch tabs. Lower the cover and operate the dryer to ensure the switch works properly. If good, align the cover with the locator pins and simply push downward on the front of the cover. It should 'pop' into place. Done! I don't have a standard crimping tool for the connectors, so I used a vise-grip to squeeze the barrels, adjusting the squeeze pressure for a second 'insurance squeeze'.