Relay in cig lighter?

[slemmer]

On a 2005 Sierra, does anyone know if the cig lighter and accessories plug is:

1. on the same circuit

2. is relay controlled

 

I've got two heated seat cushions and considering installing a 300W inverter for my kids XBox. I'd like to install a relay to maintain the output voltage when those heated seat cushions kick in...

 

Thanks

 

Sorry -- wrong forum -- it should be in the 1500/2500 forum...