Need help with K5 missing fuel gauge wiring

[1970pelle]

Hello, its been a while. I need to post an update about my health issues. I'll get that handled soon.
But in the mean time I have been helping a friend with a cool 2wd K5. That he picked up as a big basket case. Its almost all together, but for a gas gauge issue. The gauge signal wire from the front of the vehicle is know where to be found. I have searched google up and down, every manual I could get my hands on. I'm not finding anything that matches this pile of parts that have been put together. Everything else is working. Seams like it was cut off at one point. I should be looking for a pink wire to hook to the fuel sending unit. I can't find it anywhere. And I can't seam to pin point it in a manual to run a new wire to the sending unit. I'm starting to feel pretty dumb about now.
Any input great. We are working with a new gas tank,sending unit. Its a 1978 K5 with a 5.7L carb engine with a 700r4. And it's 2wd.

Thanks Ken