Analog input pins holding voltage despite pulldown resistors

My Arduino has been working fine for the last few weeks. I powered it up today, and noticed that my analog inputs each read a steady (but unique) voltage between 1.5-3.5 V.

If I connect the inputs directly to ground, they will be grounded (obviously). But if I connect them to ground through even a small 220 ohm resistor, they maintain a voltage between 1.5-3.5 V.

Can anyone advise me on this issue? Many thanks.

Need an image of the wiring.


Here's an example of A0 wired to ground through a 220 ohm resistor. A0 reads ~1.6 volts.

Ok, we need to see your sketch also.

Is the light green wire is plugged into A0?
Move the circuit to a different section on the breadboard.


~1.6 volts
Are you using a DVM or is this from your sketch?

I'm using a DVM to measure across the resistor. I've tried moving this circuit around the breadboard, and even to an entirely different breadboard. Here is a sketch:

A 'sketch' is Arduino code used to read the voltage on your analog pin.

Your DVM might be at fault.