New Fuel Tank Selector Switch, now no fuel level

[jdclampett]

I have a 85 GMC C3500 4 speed with 454, dual tanks. I replaced the tank selector switch the other day, and also all the instrument panel lights. After I put it all back together, I drove to work and back and noticed that my fuel gauge hadn't moved. I switched to the other tank and it twitched, that was it. I did fill up both tanks a few days ago, before switching the switch, and both tanks registered a little past full, which is fine, and before I had filled them they both registered about half tank. However knowing this truck as I do, im almost certain that my gauge should be at least to the full mark by now, not still past full. Any ideas? Thanks.

[Irish_Alley]

Do you still have the old switch?

[zieg85]

I would put my money on the plug on back of the instrument cluster not being plugged in all the way

[bake74]

I would put my money on the plug on back of the instrument cluster not being plugged in all the way

     X2 on what zieg said.

[Irish_Alley]

wow missed the details about the instrument lights lol good catch guys

[zieg85]

If it is plugged in all the way carefully unplug it and look at the copper on the plastic printed circuit to see if any are loose.  I had one that I took a dab of Gorilla glue and it fixed it right up.