Passenger side rock lights are "done". But whenever I try to connect the strand to the drivers side strand they all cut off. I believe it's grounded good on the rear. I can't figure this out
are you running them all in series (one pod connected to the other conected to another, ect) or are the all parallel wired (each pod has a home run back to the switch or power source)?
If in series; you have to many on one run, start another parallel series of light for the other side, wire the sets back to the same switch.
^ yeah. I've been researching this for a couple years for my rig.
they say you should wire a few together at a time (2-4) then run power to the next set. 1 resistor for each set. Or you can run full power to each (12V) and run a 470-560 Ohm resistor at the LED (for most blue & white), I've switched to the 560 Ohm, a little less power, but you're much less likely to burn them out.
(our Alt. can put out 14.2V a bit more that 12V)
you can run all these power leads to 1 wire (or 2 into 1 left-right) then on to switch, and you can ground just about anywhere to body.
I think your problem is, you are not getting enough power to your LEDs.
It sounds like with both sides on you only have enough power for 1 side, or 1/2 of your LEDs.
Try this resistor calc:
http://led.linear1.org/led.wiz
also more info if you look around the site.