so I have installed my xm radio and I love it .... It's the hardwire commander mt the only problem is I have it hooked up to a power line that is always on and I somethines forget to shut off power switch on the radio ... I need help finding wire that shuts off when car is off I tried the cig lighter but no power comes out only when it has right plug in it (weird I know)

 

you tap the cig lighter correctly?
(my guess is no.. black is positive.. white with black stripe is negative..)

it's a power source that's fine for what you're askin'

 

plus its a power source that is only hot when the car is on, double fine for what you're askin'

 

yup, it the easiest one to get a hold of too.

 

speaking of hooking up to the cigarette lighter....i had the idea of using a block terminal for various things i may want to hook up to the 12v line. Are there any forseeable problems with this? Anyone know what the maximum total amperage is on a dc line like that?

 

the fuse on the cig lighter is 15A

block terminals are more suited getting power directly from the battery.