AC comes on blows cold 3/4 miles down road radio,powder windows shut off

What is your question?

comes right back on,repeats 3 to 4 miles down the road,battery tests fine, alternator tests fine, could this be a relay issure?

What makes this problem better or worse?

only when AC is on

How long has your 2007 Chevrolet Trailblazer had this problem?

1 month