I have a 94 F-150 4.9L duel tanks replaced both sending units and the rear tank is drawing fuel from the front tank. I know it is a check valve issue in the rear tank. There are two part numbers for the sending unit F6TZ9A407CC and FOTZ9A299CB. Now the FOTZ9A299CB is discontinued the F6TZ9A407CC is available which i bought and having the issue with. My question is the part number I bought (F6TZ9A407CC) also includes the Bronco, which doesn't have duel tanks, would the pump have the built in check valve? If not then what is a cross number for FOTZ9A299CB

 

A tank can't "draw" fuel from anywhere. The sender is what sends the fuel level signal to the gauge. The FDM contains the pump & all the valves, and it's the same for pickup front & Bronco rear tanks; pickup rear tanks use nearly the same FDM, but it has a tilted sock. Read this page:

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If the new part is defective, return it for exchange or refund ASAP.