6.6 Control Board and Electrical Component Diagnosis

Modern dryers rely on sophisticated electronic control systems that manage heating operation, timing, and safety functions. Control board failures can cause various heating problems including no heat, intermittent heating, overheating, or incorrect temperature control. Understanding control system operation and diagnostic procedures helps homeowners identify electrical problems and determine when professional repair is needed.

The main control board, often called the user interface board or electronic control board, receives input from temperature sensors, user selections, and safety devices to control heating operation. It sends signals to heating elements, gas valves, igniters, and other components based on programmed logic and sensor feedback. Control boards contain sensitive electronic components that can fail due to power surges, moisture, heat, vibration, or component aging.

Common control board symptoms include display problems, incorrect cycle operation, heating system not responding to user selections, erratic heating behavior, or complete system failure. However, these symptoms can also indicate other component failures, making proper diagnosis critical before expensive control board replacement.

Diagnostic procedures for control boards typically involve checking input and output signals with a multimeter or oscilloscope. However, this requires advanced electrical knowledge and access to technical service manuals with specific voltage and signal specifications. Most homeowners should focus on eliminating other potential causes before suspecting control board failure.

Basic electrical checks homeowners can perform include verifying proper voltage supply to the dryer, checking wire connections for corrosion or looseness, and ensuring all sensors and switches provide proper signals to the control board. Intermittent electrical connections often cause symptoms that mimic control board failure but cost much less to repair.

Power supply issues frequently affect control operation. Dryers require stable 240V supply (for electric units) or 120V plus gas supply (for gas units). Voltage variations, loose connections at the electrical panel, or inadequate wire sizing can cause control problems that appear to be board failures. Professional electrical evaluation may be needed if power supply problems are suspected.

Wiring harness problems become more common as dryers age. Wire insulation can become brittle, connections can corrode, and repeated vibration can cause wire breaks. Visual inspection of accessible wiring and connector cleaning can resolve many apparent control board issues at minimal cost.

When control board replacement is necessary, costs typically range from $150-300 for the part plus labor. Exact model compatibility is crucial as control boards are specifically programmed for individual dryer models. Generic or "universal" control boards rarely provide proper function and may cause additional problems.