I've put LED's in the footwell, I want to splice them into the bulb that lights up the automatic shifter, (P,R,D,3,2,1)

To ground it, can I just splice the ground wire for the LED's into the ground wire for the shifter bulb, or do I need to ground it separately to metal?

Also, there are two sets of lights so there are two sets of wires, do the two ground wires have to be grounded separately or can I splice them together?

 

you shouldn't have an issue just running all the grounds together. LEDs take almost no juice to run. I would refresh the existing ground and make sure you get a good splice into it.

 

You can ground the negative wires separately or by splicing into the existing lamp wiring or in any combination, whichever is most convenient.

You may be thinking about certain audio wiring where multiple ground points can cause noise.

 

x3^...You can ground the led's anywhere. A note, be careful how you rout the positive. If it shorts and blows the fuse it will take out your tail-lights too I think. (then you will have bright lights in the rear view mirror!)