1978 Aux Fuel Tank selector - Location?

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Mark97213

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Hello all. I'm rebuilding the interior that was completely removed by the previous owner. I'm trying to find the location of the Aux fuel tank selector switch. There was no switch attached to the wiring when I got the truck but now that I have the switch, I cannot find where this switch is supposed to be mounted. On newer trucks, it mounts directly into the dash with the switch bezel mounting an top but there is no such location on the dash of the 1978.

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78C10BigTen

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My 78 it is just to the left of the ash tray.
 

78C10BigTen

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Not my truck but its the hole to the left of the ash tray hole under the air vent hole. Id draw a circle around it but my phone wont let me...

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Mark97213

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Yeah, that's the same location as my 81 and 85 but there's no such hole in the dash in my 78. I thought maybe someone filled it in but that's not the case, it's factory. The 5 prong connector to the left is factory as well. Baffling.[/QUOTE]

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K201979

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my 79 has it in the same spot.
 

Mark97213

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[/QUOTE]

That switch is for an 81-87 according to LMC

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Rickf

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Maybe your truck is set up for a single tank.
 

Mark97213

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Maybe your truck is set up for a single tank.

Perhaps that's it but as you can see, there is a factory connector for the switch. I suppose someone could have added the Aux tank, and all the wiring and valve but seems unlikely. I just don't know.
 

DoubleDingo

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Have you felt around on the back side to see if maybe someone for some crazy reason decided to patch the hole?
 

Mark97213

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Yes, that's exactly what I thought as well but I can see clearly behind it that it's never been cut or filled. It's an OEM dash with nothing there. It's weird.

The 73-80 switch doesn't have a bezel around the switch (see above switches) like the 80 and newer ones did. If you look at the 73-80 switch in the diagram, it doesn't seem like it would mount in the dash based on the switch design.
 

Kasey 1977 K10

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My '77 with dual factory tanks has the switch left of the ashtray as well.
 

Kim Burke

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My 79 is in the same left of ashtray position. That’s weird that there’s no hole. I’d just drill four corners metabo the sides and put a square hole in the dash and be done with it.
 

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