Fuel Tank Selector Switch Wiring - Quick Question

[Evil Trailblazer SS]

So, the tan/white wire which is the 12v feed to the dash switch is currently NOT WIRED properly!

The tan/white wire leads out the grommet in the firewall to the engine bay, but at some point some clown (for God knows what reason) popped the grommet and disconnected the tan/white wire from wherever it was supposed to be wired and fed it back through the firewall into the cab and connected it to the extra ignition 12v+ pink/black wire behind the headlight switch coming from the main fuse panel.

So, where is this tan/white wire supposed to go in the engine compartment? I found an obscure post on some random forum that it goes the the fuel pump relays (on passenger side of the firewall?) to a red wire, is this correct?

I am getting so sick of other peoples' hack jobs! But I am glad I am actually finding them!
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[VetteVet]

there are variations to the switch and valve wirings. Here is what you should do.
Go to the little box up top by the PM notices and type in "fuel tank selector switch", tick the 67 to 72 trucks box and click Goggle. It will take you to a page of threads on the subject and you can read them to see if they apply to your truck. Pay specific attention to this one. http://67-72chevytrucks.com/vboard/s...d.php?t=399260

I have to leave for town soon so I will check back in later to see if you have made any progress.

[justpball]

See if these help bro


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[hatzie]

What Model year is your truck?

[Evil Trailblazer SS]

1987 454 TBI...the wire colors on all of these schematics I have seen are different than what is in my truck.
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[justpball]

Dang sorry bro! Mine is an 87
And mine matched these colors
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[Evil Trailblazer SS]

No worries man! Anything helps honestly! I am really only wondering where the Ignition 12v connects to. On my truck it is the tan/white wire that leads up to a grommet in the firewall right next to the throttle cable. After it goes through the firewall, where does it connect?
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[Evil Trailblazer SS]

I figured out what some jackass previous mechanic did to the fuel pump selector wiring. The tan/white wire that feeds the 12v+ signal to the selector is supposed to run out the firewall near the accelerator cable and then down to the main harness where there is a tan/white wire with a single gray connector. This wire is listed as circuit 120 in the diagram below.

The way it was wired was totally wrong. The tan/white wire was run out the grommet in the firewall, then the grommet was pulled in to the cab where the wire was run back into the cab and over to a random pink/black ignition 12v+ connector that basically eliminated the fuel module. I figured out something was wrong when I would turn on the ignition and the fuel pumps would run constant, no 2 second prime and then off.

The reason none of the wiring diagrams listed above helped was because only the 1-Ton 454 and >8500gvwr trucks had this fuel module so the circuits are different.

[justpball]

Glad you finally got it bro!
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