using both 5v pins

why when I use both of 5v pins on my Arduino uno shield, all the Arduino is shutting down? (no light from the lcd/leds, like its not connected to power)

I'm betting you're overloading the poor power supply, causing it to thermally shut down.

What, exactly, are you connecting to the 5V pins? Things like GPS modules or backlit LCD displays can be huge power hogs.

Jiggy-Ninja:
I'm betting you're overloading the poor power supply, causing it to thermally shut down.

What, exactly, are you connecting to the 5V pins? Things like GPS modules or backlit LCD displays can be huge power hogs.

actually, I'm using only 1 of the pins to power 6 photodiodes, 6 IR leds and servo motor but i wanted to make the servo motor in other place so i decided to just plug it instead together with everything to 1 pin i wanted to put it in the other side so there wont be a cable mess, and it just shutting down if I'm using both of the pins for some reason.

I just pulled out one of my Arduinos to check, and there's only one 5V pin. "Both" implies that you are using two. What is the 2nd pin you're talking about?

Your English doesn't seem very good (like it's not your native language), so I don't think you're describing what you're doing properly. Can you take a picture or draw a schematic of how you have things wired up?

What shield are you using?

On the UNO, the IOREF pin is connected to the 5V pin, I think it's for feeding 5V up to a shield.

tinman13kup:
What shield are you using?

He's a student, and (per another thread of his on this same project) he's using the abomination pictured here:

Can't comment on how he's connecting things in this case, ofc, but he's got this wierdo "educational" shield four times the size of the board that looks to be of marginal design at best.

Oh. That looks interesting. It does explain using more than one 5v pin though. That is the inevitable outcome when anyone can design up a board, get it produced at a board house, and throw it on ebay. It seems to lack any particular purpose, so they just threw everything on it.

So either the shield is faulty, or something was improperly wired when OP rearranged things to use the other 5V pin.