Gauge cluster - wiring Question?

[alvald83]

I have a '69 that i just pepainted the dash cluster and have a question about which orange wire should be connected to the back of the cluster that is named "Orange". I have an orange wire that is coming from the cluster harness seen in Photo 1 and another orange wire coming from the behind the dash (seen in photo 2).
I believe the dash orange wire was connected to the cluster. And with that wire connected, only the main tank level (tank behind the seat) could be seen on the gauge. I flipped the tank toggle switch but only the main works.
My Aux. tank has never shown anything since i have owned the truck. I assumed it was the sending unit and never bothered replacing it.

[basketcase0302]

which orange wire should be connected to the back of the cluster that is named "Orange".

Both of those orange wires should be from your sending units if I'm not mistaken. I believe it will be the wire in the top photo you need to hook up to get just the in cab tank sending unit powered. I would run a continuity check across the orange in the bottom photo to verify if it is from the aux tank sending unit. For both tanks to read-both sending units wiring goes to the tank selector switch, and the "center pole" from the switch feeds the gauge. Here's a diagram that might help:
http://www.fordification.com/tech/wirin ... rpanel.jpg
I'm not sure if I've ever seen the dual tank switch wiring diagram here or not, BRB if I find one?

[alvald83]

Well, i was thinking that the dash orange wire would go to the tank gauge switcher, but that switch just has a multiple wire plug. If that wire is indeed coming from the sending unit, where would it go?

[basketcase0302]

I can see your dual tank switch in the one picture just below your headlight switch. You should have one wire from each sending unit, (the orange wires from each sending unit) on that switch. And the other terminal on the switch feeding the gas gauge, (the "orange" terminal in your picture on the back of the instrument panel). I can't remember which terminal-which wire as I pulled my switch out several years ago. Normally on a single pole-double throw switch the center will always have continuity, (the gauge wire would go there) but you'd probably need to verify this with an ohm meter.
This diagram might help more: