I'm trying to figure out if the whole fuel system is working on my '89 f350 with a 7.3. Last thing I'm working on is switching from tank to tank, and after reading here I read that when I flip the switch I should hear the selector valve buzz or make some noise. When I flip the switch I can hear the valve make a clicking sound, does that mean mean its working properly? Thanks guys

 

https://www.ford-trucks.com/forums/9...tor-valve.html Have a read here, may help.