hello I am helping my sister with a 07 LS. she wanted to get rid of her steel wheels and caps. So I found a nice set of GM alloy wheels from a 04 Impala SS. her original wheels have the metal valve steams. so can I remove them and put them on the alloy wheels to get rid of the light on the dash

 

As long as the wheels you now have are compatable with the valve stems from the stock rims then you can do this, certainly worth attempting if you are able to switch them out yourself.

 

well the problem is both sets of wheels are mounted on the wheels

 

Then you'll have to go to a tire-place to have them remove the wheel, swap the sensors and remount the wheel.