The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

ray_mcavoy · 12-31-2012, 11:06 PM

Hi Rick,

If no one else chimes in with pics, I can get some of my dad's 77 GMC K15 tomorrow.

Just be aware that GM used a few different setups over the years. The early style ones use a solenoid valve to switch the tanks. It only has 1 wire connected to it and the dash switch takes care of switching the gauge sending unit connections. The later years use a motorized valve that switches the tanks and the gauge sending unit connections. These have a 5 wire plug. I'm not sure what style is correct for your 78 but I know 77 was still using the older 1-wire solenoid valve.

There are also 3 and 6 port selector valves. The 6 port ones are used on trucks that have a return line running from the fuel pump back to the tanks. A quick look at your fuel pump will let you know which one you need.

12-31-2012, 11:06 PM	#2
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,373	Re: fuel selector valve question Hi Rick, If no one else chimes in with pics, I can get some of my dad's 77 GMC K15 tomorrow. Just be aware that GM used a few different setups over the years. The early style ones use a solenoid valve to switch the tanks. It only has 1 wire connected to it and the dash switch takes care of switching the gauge sending unit connections. The later years use a motorized valve that switches the tanks and the gauge sending unit connections. These have a 5 wire plug. I'm not sure what style is correct for your 78 but I know 77 was still using the older 1-wire solenoid valve. There are also 3 and 6 port selector valves. The 6 port ones are used on trucks that have a return line running from the fuel pump back to the tanks. A quick look at your fuel pump will let you know which one you need.