That one gets enabled. When the main tank gets down to 1/4, the BCM activates that circuit, which completes ground on the fuel transfer relay coil, which activates the secondary fuel pump to start transferring fuel into the main tank. Once the main tank is 7/8 full, it shuts off. If it isn’t already there, you’ll need to add this wire on BCM connector C1/A pin 16. That wire goes to PDC (fuse box) connector C6 pin 16, which is #86 on the fuel transfer relay. From there, you’ll run a wire from PDC connector C6 pin 20, which is #87 of the fuel transfer relay, to the aux fuel pump motor.
There’s no circuit on BCM connector C1/A pin 17, so I’m guessing you meant C5/E. Pin 17 on the C5/E connector is the main fuel level sensor, and pin 15 on the C5/E connector is fuel level sensor 2. In AlfaOBD, you’ll be looking to enable connector E pin 15 (or pin E15). I’m not seeing that in the list, so hopefully it’s already enabled.
