Rear Fuel Pump - Dual Tank Applications Only
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
On dual tank applications, The rear fuel pump is located in the rear fuel tank. The rear fuel pump is powered by a secondary fuel pump relay when the fuel level drops below a predetermined value. Fuel is transferred from the rear fuel tank to the front fuel tank in order to ensure all of the usable fuel volume is available to the front fuel pump. The rear fuel pump relay supply voltage is received from the primary fuel pump relay when the front fuel pump is energized.