Best guess: you have an intermittent open or short circuit in the wiring. More than likely, it's near the sending unit wire. If it's the slip on type, remove it, clean it, and make sure the small strip of metal inside the plug isn't cracked or bent. If it's the screw on type, check the connection at the sending unit again. If both are OK, then I would guess it's in the harness. You may have pulled on a wire when you changed the unit, closing the circuit, but over time, the vehicles vibration caused the circuit to open again. The same applies if it's a short circuit. The vehicles vibration causes it to open or close once in a while, making the gauge work sometimes, and stop working sometimes, as you explained.
|