08silveradobrad: ANSWER TO YOUR Q. THIS MAKE & MODEL IS VULNERABLE TO WATER INTRUSION INTO THE SPEAKER WIRE TO SPEAKER CONNECTOR. WHAT I HAVE FOUND ON NUMEROUS OCCASIONS IS THAT MOISTURE GETS INTO THE CONNECTOR THAT SNAPS INTO THE SPEAKER & THE CONNECTOR & SPEAKER TERMINALS GET CORRODED WHICH CAUSES SPEAKERS TO CUT IN & OUT AS THEY RECIEVE & LOOSE THE CONNECTION ( AND EVENTUALLY THIS WILL CAUSE SPEAKER FAILURE). THE FIX IS TO REPLACE EITHER THE AFFECTED SPEAKER OR JUST DO THEM ALL AT THE SAME TIME. BUT ALSO THERE IS A WAY TO KEEP IT FROM REOCCURING. REPLACE THE SPEAKER & IF THE CONNECTOR TERMINALS ARE CORRODED IT IS A GOOD IDEA TO REPLACE THE CONNCTOR TOO. IT IS ONLY TWO WIRES, MAKE SURE TO CRIMP THEM TOGETHER NICE & TIGHT & USE EITHER HEAT SHRINK TUBING OR HEAT SHRINK BUT CONNECTORS. MOST IMPORTANTLY TO KEEP FROM HAPPENING AGAIN!!, BEFORE CONNECTING SPEAKER TO CONNECTOR PUT A PEA SIZED GLOB OF DIELECTRIC GREASE (COMMONLY CALLED TUNE UP GREASE BECAUSE IT IS USED ON SPARK PLUG WIRES ALSO TO PREVENT ARCHING) DIRECTLY ONTO THE END OF THE CONNECTOR, THEN SNAP THE CONNECTOR ONTO THE SPEAKER. THIS WILL PREVENT ANY WATER OR FOREIGN MATERIAL FROM ENTERING THE CONNECTOR & CORRODING THE CONNECTOR TERMINALS & PINS AGAIN. HOPE THIS HELPS. I HAD A 08 SILVERADO TODAY ACTUALLY THAT HE CUSTOMER STATED SPEAKERS CUT IN & OUT BUT THE TWEETERS WORK OK. WELL WHEN I GOT IT & INSPECTED IT ALL OF THE DOOR SPEAKERS, FRONT & REAR WERE INOPERABLE. THE TWEETERS WORKED. I REMOVED DOOR PANELS & FOUND CONNECTORS ON VEHICLE SIDE & ON SPEAKER SIDE CORRODED & THAT WAS MY FIRST CLUE THAT DUE TO WATER INTRUSION INTO THE CONNECTOR THE SPEAKER WAS DAMAGED. I PLUGGED IN A KNOWN GOOD SPEAKER & WALLAH. ALTHOUGH IF CONNECTOR & SPEAKER & DIELECTRIC GREASE ARE NOT INSTALLED THE CORROSSION WILL BUILD UP AGAIN & CAUSE CORROSION SHORTLY DOWN THE ROAD. ANYWAY HAD TO REPLACE ALL FOUR SPEAKERS, CONNECTORS & PUT DIELECTRIC GREASE IN CONNECTORS.