[JRTJH]

On some 12VDC motors there are connections on the outside that can be fixed by tightening the screws on the terminal block. On some, there is a plug and internal connections. On that type, the motor has to be disassembled to repair the connections to the brushes. Here is a "sort of the same" DC motor. You can see the wires going to the brushes. If those wires are shorted out, open, loose or if the brushes are worn, that may be the problem with intermittent function.