Wire to the wrong side of switch.
On your first post you stated that camera dies when the engine starts.
Now you stating that camera runs but dies after a while. So I would look for a power relay or circuit breaker that is heating up and stops working after it heats up or loose ground.
You will have to follow the wire or shoot it with a wire tracer.
check the ground first then the breaker or relays.
I assume you are now plugging into a cigarette lighter socket using a different plug and wire and the unit stays on.