the oven on my mer7700lz won't heat up at all, but the lights and controls all seem to work fine.

Diagnosis

The most frequent cause of a total loss of heat in the Maytag MER7700LZ, while the display remains powered, is a catastrophic failure of the bake element (Part #WPW10173131). Because the control board and the user interface are on a separate circuit path from the heating elements, the clock and buttons will continue to function even if the heating circuit is completely open. This usually occurs when the internal resistive wire breaks or the outer sheath develops a pinhole leak, allowing oxidation to destroy the heating coil. To confirm this, look for "hot spots" or blistering on the element's surface. However, since these failures are often internal, the element may look perfect but be electrically dead. If the oven doesn't even attempt to "click" into gear (the sound of the relay engaging on the control board), the issue could be a blown thermal fuse or a failed relay on the Oven Control Board (OCB). If the relay clicks but no heat appears, the element is the culprit. You can verify this by using a multimeter to check for continuity across the element terminals; a reading of "OL" (Open Loop) confirms the element is burnt out.

How to Fix It

1. Disconnect the range from the 240V power source. Unplugging the unit is mandatory; do not rely solely on the circuit breaker.
2. Remove the oven racks and the bottom heating element cover if applicable.
3. Locate the bake element terminals at the rear of the oven cavity. Remove the two screws securing the element flange to the oven wall.
4. Carefully pull the element forward to expose the wiring. Use a needle-nose plier to disconnect the two spade connectors from the element terminals. Note if there is any scorching or melted plastic on the wire connectors.
5. Inspect the new element for any shipping damage. Slide the new element into the oven cavity, ensuring the flange sits flush against the rear wall.
6. Reattach the spade connectors firmly. If the connectors feel loose, gently squeeze them with pliers to ensure a tight fit, as loose connections cause arcing and premature failure.
7. Secure the flange with the two mounting screws.
8. Restore power and set the oven to "Bake" at 350°F. Feel the element after 60 seconds to confirm heat production.

If That Didn't Work

• Test the Thermal Fuse: Locate the thermal fuse (temp switch) typically mounted on the rear chassis. Use a multimeter to check for continuity. If the fuse has blown, it breaks the circuit to the elements to prevent a fire. Replace the fuse and check for any obstructions blocking the rear vent airflow.
• Inspect the Oven Control Board (OCB): Examine the back of the main control board for "burnt" spots or blackened solder joints around the heavy-duty relays. If the board has a failed relay, it will not send 240V to the element even if the display says "Heating." This requires a full board replacement.
• Check the Broil Element: If the bake element is dead but the broil element (top) still works, the issue is isolated to the bottom element or its specific wiring. If neither works, the problem is likely the thermal fuse or the main power supply to the heating circuit.
• Verify Voltage at the Element: With the oven turned on (exercise extreme caution with live voltage), use a voltmeter to check if 240V is reaching the element terminals. If voltage is present but the element isn't heating, the element is defective. If no voltage is present, the break is further up the line at the board or fuse.

Heads Up

• Avoid using "oven cleaner" directly on the heating elements, as the caustic chemicals can degrade the outer sheath and lead to premature element failure.
• Always check the spade connectors for "browning" during replacement; if the wire is charred, cut back the wire and crimp on a new high-temperature terminal to prevent a fire hazard.
• Ensure the oven is perfectly level. An unlevel range can cause uneven heat distribution and put undue stress on the oven cavity seals.
• If you replace the control board, remember to perform a factory reset by cycling the breaker off for 30 seconds to clear any stored error codes.