GMC Repair: fuel pump, fuel pump relay, tank applications

Question
2001 gmc single cab flatbed dual tanks.which tank has the fuel pump.      transfer pump?

Answer
On dual tank applications, The secondary fuel pump is located in the secondary fuel tank. The secondary fuel pump is powered by a secondary fuel pump relay when the fuel level drops below a predetermined value. Fuel is transferred from the secondary fuel tank to the primary fuel tank in order to ensure all of the usable fuel volume is available to the primary fuel pump. The secondary fuel pump relay supply voltage is received from the primary fuel pump relay when the primary fuel pump is energized.

The Primary pump is located in the front tank.
The secondary pump is located in the rear tank.