I cannot use the dome light power where it is mounted at, because it goes off.. Do I need to run other line or is there to make the D.C. stay on? 2008 Mega cab.

Thanks for any input..

 

I'd say this would have gotten more responses in the truck forum, but you should certainly run a separate [edit] FUSED [/edit] power lead and ground lead.

Even if you could fool the dome light into staying on, it likely would not be safe to run other appliances off the side wire going to it as most wires are rated for a certain amount of power and if you exceed this, you can melt the casing and cause electrical failures, or worse, fire.

As a side note, 14-18 gauge wire should be sufficient for the majority of DVD and LCD combos. However check out the manual and find power requirements. You might also want to 'look into' your local laws regarding entertainment displays and their visibility to the driver while moving.