A friend of mine asked me if I could identify a component that keeps causing the flow of current to stop in a 12 V 1 motor system he has increased to 2 motors (perhaps due to overload or heat). He says that when he by-passes this particular component the circuit no longer shuts down, but the wiring starts to get very hot/melt.
The component looks quit old and has some numbers on it but I could not find out anything about it. I think he uprated the battery to cope with the 2 motors but the extra current is causing this component the shut down the current flow temporarily. I have added a picture. Any suggestions?