12V PWM gauge control

I'm using a tutorial to control an automotive gauge, It was originally a voltage gauge but I modified (Change a resistor) to be an oil pressure gauge (12V full scale), I can control it as it should, using a 2n3904 like this, without the POT and 12V instead of 5V, the 50k get replaced with a 10ohms to give 12V a full scale (it takes 0.03a):

Same connections, output pin 9, but also I'm using a Nokia lcd 5110 (exactly the same config. as the spark fun basic tutorial), as soon as I start both LCD and PWM gauge control, the LCD turns off and I think that its protecting, if I sweep the gauge on startup and then show some LCD text, it works, both things.. LCD gets off, am I doing something really bad? both arduino and gauge are powered by a 12V regulator, share the same ground. :astonished:

Nothing obviously bad.
Is your LCD using the same pins?

Otherwise it looks like it is not actually wired up like you think it is.

I'm doing something like this, without the pot on the nokia LCD and using a level shifter for the 5 to 3.3v on the arduino outputs (just like the adafruit page)

So in fact not like that at all.

We need a schematic not an abortion like that of what you actually have.

I just replaced the 2n9304 with a TIP120 and works as intended.