I have read a ton of posts on this part but cannot find it anywhere on my truck, do all dual tank trucks have this? I have had my bed off and replaced both fuel pumps, and traced the fuel lines all the way to the fuel rail, but haven't located this anywhere. The only thing I have found is a crappy black plastic block in the frame rail (near the trans) with return lines running into it. The only reason I care is that my tanks seem to switch only when they want to. I have replaced the fuel selector switch on the dash but the pumps dont run correctly. The rear will run, or both will run. I cant get just the front pump to run. I thought the selector valve may be the source of the problem......But I cant find it! Any help would be great.

 

No you do not have a fuel selector valve on a 1991 F-series Gas truck.

Sounds like a wiring problem.

Do you have a photo of this item?

 

ok, thanks for the reply. That narrows it down alot!