1997 BMW 318i Transmission control solenoid

I'm assuming you're looking for a transmission control module is located in the engine compartment on the right side against the firewall

Sorry it's actually the shift solenoid

I apologize, the shift solenoids are controlled by the transmission control module if I understand you correctly you want to get into the valve body of the transmission and replace the shift solenoid?

Yes that is it.

I am having a hard time finding information on that transmission, but here is a schematic of it what I would do is remove the pan and the shift solenoid should be plugged into the valve body number 13. Hope that helps you out.

I found a better pic of the valve body that shows all the solenoid