I've got a voyager in-visor cam. Of course, Voyager isn't made anymore.
Put the key in the ignition, the camera comes on. Start the rig and leave it running, 90% of the time the camera goes non-responsive. If you stop and start it a few times, it might come back.
Faced with replacing it for $300, I put a re-set switch in. Once started, if it doesn't behave, just press the switch.