‘75 C30 Fuel Tank Selector Knob

[Luvrv8]

interesting. any pic of the "switcher" that the cable operates?

Didn’t take one. I believe it’s 6 ports and the cable operates it. It’s on the right hand inner frame rail, no electrical as the fuel gauge sending units are wired to a switch behind the dash that is triggered by the cable.

 

[AuroraGirl]

Didn’t take one. I believe it’s 6 ports and the cable operates it. It’s on the right hand inner frame rail, no electrical as the fuel gauge sending units are wired to a switch behind the dash that is triggered by the cable.

if you can ever take a pic of the actual unit that would be appreciated, no rush tho. Just curious myself.

Did this truck use leaded gas originally? Im just wondering why its a mechanical valve and not a electrical like the trucks

 

[Luvrv8]

if you can ever take a pic of the actual unit that would be appreciated, no rush tho. Just curious myself.

Did this truck use leaded gas originally? Im just wondering why its a mechanical valve and not a electrical like the trucks

California banned leaded gas in the early 90’s. As far as the switching unit being cable, no idea. I have seen where some mentioned in ‘75 it only came in Cab and Chassis with a Big Block. I haven’t found anything to confirm this. I’ve also seen that many have been swapped to electric due to parts not being available

 

[Grit dog]

And I know it came off as rash, I am sorry for that and not the way I wanted to start as a newbie.

You didn't, and it didn't come off that way. Cheers!
That's a pretty clean truck based off the business end pictures.

 

[Grit dog]

California banned leaded gas in the early 90’s. As far as the switching unit being cable, no idea. I have seen where some mentioned in ‘75 it only came in Cab and Chassis with a Big Block. I haven’t found anything to confirm this. I’ve also seen that many have been swapped to electric due to parts not being available

Obviously it has nothing to do with leaded gas, but I've been wondering the same.
If I had to guess, the electronic tank switching solenoid was "new" to GM pickups in what? '74? (I know 74 had dual electric switch tanks and thought I read no dual tanks offered on first year models in 73?)
Either way, I'd hazard a guess that the C&C may have received the dual tank feature in a more utilitarian way (possibly thought or advertised to be more "reliable") vs pickups with greater "creature comforts."

 

[Bextreme04]

I had a 74 C20 and it had the normal electric switching dual tank setup. I had read somewhere about a few years using that cable version, but I'm not sure what the specifics are

 

[AuroraGirl]

Obviously it has nothing to do with leaded gas, but I've been wondering the same.
If I had to guess, the electronic tank switching solenoid was "new" to GM pickups in what? '74? (I know 74 had dual electric switch tanks and thought I read no dual tanks offered on first year models in 73?)
Either way, I'd hazard a guess that the C&C may have received the dual tank feature in a more utilitarian way (possibly thought or advertised to be more "reliable") vs pickups with greater "creature comforts."

this would make sense. akin to getting a hand throttle to operate a pto easier too like was possible.

 

[Luvrv8]

Obviously it has nothing to do with leaded gas, but I've been wondering the same.
If I had to guess, the electronic tank switching solenoid was "new" to GM pickups in what? '74? (I know 74 had dual electric switch tanks and thought I read no dual tanks offered on first year models in 73?)
Either way, I'd hazard a guess that the C&C may have received the dual tank feature in a more utilitarian way (possibly thought or advertised to be more "reliable") vs pickups with greater "creature comforts."

I’ll guess since the majority of cab and chassis were being sold to fleets GM put the cheaper of the 2 on.

 

[Luvrv8]

A quick set of pictures I got while crawling around on the concrete of the switcher valve. The one wire you see cut, that’s a crazy story. The fuel gauge would only work when the e brake was at a certain spot. I did check the pressure differential switch, electrical wasn’t mixed up. I did ohm checks on the printed circuit board, it wasn’t the issue as I thought maybe it bled over to the fuel gauge. I checked the sending units, ohms checked out. That wire is going to the engine compartment and then returns to the spot you see, honestly I didn’t spend time seeing where it went I just bypassed it and the fuel gauges worked since. It’s on the list of a couple other items to figure out.

 

[AuroraGirl]

A quick set of pictures I got while crawling around on the concrete of the switcher valve. The one wire you see cut, that’s a crazy story. The fuel gauge would only work when the e brake was at a certain spot. I did check the pressure differential switch, electrical wasn’t mixed up. I did ohm checks on the printed circuit board, it wasn’t the issue as I thought maybe it bled over to the fuel gauge. I checked the sending units, ohms checked out. That wire is going to the engine compartment and then returns to the spot you see, honestly I didn’t spend time seeing where it went I just bypassed it and the fuel gauges worked since. It’s on the list of a couple other items to figure out.

thank you thats cool!

 

[Luvrv8]

Not sure it’s the factory knob but it works. Hopefully some day in my travels I’ll find a GM parts manual to see exactly what was there. Who knows, when I pull the seat to repair the slides it could be under there. Wanted to make sure I did show the knob on, it might help someone search for this down the road.

 

[bucket]

What a cool setup! I definitely learned something today!