Pontiac Bonneville Rear Window Defroster

When I Push The Button For The Rear Defrost The Whole Rear Windshield Shatters In A Matter Of Seconds.

Why Does Rear Windshield Shatter When I Turn On Rear Defrost?

My Car Tries To Shut Off If I Use The Power Windows Or If I Turn On The Rear Defrost.

I Am Working On 1995 Pontiac Bonneville For A Friend. She Was On The Highway And Said The Car Just Died And Wont Start, So I Had Her Tow It...