Maytag wall ovens have a burner on the top and bottom, and each burner has a bake switch attached to it. This switch sends a signal from the control panel to the burner. If the switch burns out, the burner will not turn bright orange. If the switch is worn out or old, the burner will turn red rather than orange yellow or white. Fix this by replacing the switch.
Baking coils can get old and wear out over time. When this happens they will either not turn bright orange at all or they will only turn bright orange in several sections along the coil. Inspect the coil for small bubbles or holes that indicate it needs to be replaced. Replace the coil by obtaining a a part directly from Maytag or from a retailer that sell Maytag parts.
Electrical shorts or improper installation of a wall oven may prevent the oven coils from working. In this case there is nothing wrong with the oven. Rather, the electrician who installed it may have used the wrong wiring or failed to make the correct connections. Pull out the oven and recheck the connections to fix this issue.
Since oven coils may not stay bright orange the entire time they are on, it can be tough to determine if your machine is broken or if the color change is normal. To determine this, place an oven thermometer in the oven and check it every few minutes to ensure that the oven is maintaining a consistent temperature.