Abstract: Photovoltaic module failure detection devices and methods provide reliable, low cost, and effective solutions with visual indication of a temperature of diodes during installation, commissioning, operation, and/or maintenance. Indication of diode temperatures and/or detection of diode failures assures proper installation, improves output, expedites maintenance, increases safety, and/or raises reliability. A photovoltaic module for converting light into electricity includes one or more solar cells, and a transparent front sheet disposed over the one or more solar cells. The photovoltaic module includes a back sheet opposite the transparent front sheet, and one or more electrical circuits with one or more diodes connected to at least a portion of the one or more solar cells. The module includes one or more temperature indication devices in communication with at least a portion of the one or more diodes and disposed between the transparent front sheet and the back sheet.