Low Fuel Light not working

[PrintTech]

This is for a 1986 K100. Having dealt with the gunky fuel tank issue from fuel sitting for way too many years. Replaced the fuel pump, filter and lines. I also cleaned the fuel level parts, both for the gauge and the light. I get an open circuit when the float is up and about a 100 ohms when it is down. The issue is I never get a low fuel light. I pulled the bulb - it's good. I waited, as I read somewhere the circuit isn't instant to allow for fuel slosh. I finally pulled the connector and jumper it for a dead short as well.  Still no light. I'm looking for some ideas!! Thank you!!

[Scott_]

At the tank connector, when the float gets low enough the white wire is connected to the brown(ground) wire to turn on the dash indicator.

[PrintTech]

I've pulled and cleaned the float circuit in the tank. It had a lot of corrosion from ethanol fuel.  I get good a good connection when the float lowers. I've replaced the tank connector as it was flaky at best. A part time fuel pump was a good indicator the connection was bad. I took the instrument cluster apart. I found no bulb in the spot for the low fuel light. I moved a bulb into that spot without luck. According to the service manual there is a fuel gauge circuit on the upper left side when facing the backside. I see no evidence this board was ever installed. I'm guessing it is for an actual fuel gauge since the sender unit can send both off/on and variable resistance information. Anyway, my meter shows I am getting a change of state when the float drops. It goes from an open circuit to one with continuity, still no light.