There is a relay under the playfield that controls the motor. It sounds like the relay is not engaging to reverse the current to the motor and change direction. Either there is a problem with this board or its wiring, the relay, or the transistor that drives the relay. The transistor that drives the motor appears to be fine since the motor does work.

First thing to check is the relay board. Look for cracked solder at the header pins. This is a common problem.

If that all looks good, test the relay's coil that latches the contacts. You test it with a volt meter on ohm setting. It is a small coil with small wiring, so the resistance should be higher than what you'd see on a large coil anywhere else on the game. I'm guessing something like 20-30 ohms, that's just a guess. Could be lower.

If this all checks out, you need to check the transistor on the CPU board that engages the relay. It is Q24.

Of course double check the wiring from the CPU to the relay board (CN 12, Pin 8 on the CPU board).

This seems like a continuation of your other thread:
https://pinside.com/pinball/forum/topic/jurassic-troubles#post-2176233

Is there a reason you started a new one? I think some of what stangbat covered was mentioned in the other thread. It would be best to keep it all in the same place so we can avoid duplicating responses.