I have a 2000 Road Glide and the fuel gauge has never worked since I bought it a few months ago. I ruled out sending unit, it has good ohm readings, I replaced the gauge and still no change. I've jumped all wires going to gauge to check and still no change, all test good. I can jump gauge off signal wire at sending unit pigtail under seat and jump the + and - and gauge reads correctly but only with ignition off. When ignition is on it drops out. I was thinking it's a wire back under the seat. Any ideas? Thanks for the help.

 

Reading resistance at the indicator only and not the sender can mislead. Read the resistance at the sender and the gauge and compare readings. A bad connection may give an acceptable resistance reading but not carry the current to drive the indicator.

Check continuity to the engine and make sure you have a good ground on the sender flange.

Pull the connector off the sending unit and put a 50 - 100 ohm resistor across the wire harness connector contacts and turn it on. You should read somewhere around 1/4 to 3/4 full.

Increasing the resistor value will decrease the measured fuel level and decreasing the resistor value will increase the measured fuel level. I recently used this procedure with a 0-250 ohm variable resistor to check out my gauge. IMO, this is the best way to check out the system.

I found this schematic that might help...

Good luck!