2000 impala rr defrost interfers w/radio

I installed a new stereo and when you turn on the rear defrost the radio goes to static. Can anyone tell me what is causing this.    thank you

The antenna is part of the rear defroster grid. Try upgrading the big three and make sure the radio ground is good.

the factory harness was cut and the stereo came with an adapter.  The wire colors were the same so I matched color for color during the install.  the only off wire is a red wire that comes from the sterring column area into a 10amp fuse and then the fuse runs a red wire out that i hooked up to a red wire labeled "acc".  The prior stereo did the same thing.  I took the ground from the radio and went to ground on the firewall and the same thing happened.

The problem on happens on FM correct. It won't happen on CD. The problem is one of two things. There is a white wire in the radio harness. It needs to be connected to the radio's power antenna trigger or amp remote wire. This will power the antenna module in the car. The other issue if this didn't resolve it, is you have one or more breaks in the rear defogger grid and this causes static on the FM band. It may be hard to find the breaks, so if you can fog up the rear window with a hot beverage, turn on the rear defogger and look for the areas that aren't clearing. Thats where the breaks are. Most auto parts stores have grid repair kits to fix the problem.sparky