Bad/Blown Digital Pin?

Development Tools IDE 1.x
1

I am working with a Mega 2560 and am using pins 23 - 37 (odd numbered pins only) as digital outputs. These pins are driving the Sain Smart 8 Relay Module. In my initialization code I do a digitalWrite to set all pins high before setting the pinMode as output. (The relays are energized when low.)

As soon as I power up the Arduino pin 35 goes low. When my code toggles the state of pin 35 it doesn't change. My suspicion is that this pin may be blown, but since I'm new to the Mega 2560 I wanted to make sure that I wasn't tripping over something else. Thoughts or ideas?

2

Remove module, place LED (with resistor) on pin, test with blink sketch. Job done.

There may be restrictions on the maximum amount of current per port, but this is unlikely to manifest as a single pin failure.

3

Is that a proper relay module or a crap one? There are some awful relay modules that abuse the pin. Blown pins are often shorted to ground