The tail light wiring harness in the cargo area is not protected very well. As a result it may become damaged due to normal wear a tear. This damage can causing some or all of the rear lights to stop working.Google+
Car Problem Reports
GMC Savana 1500 Tail Light Wiring in Cargo Area May be Damaged
GMC Savana 1500 Problem
Average Mileage: 144,702 mi (20,000 mi - 312,000 mi)
Visitor, 1996 GMC Savana 1500, 180,676 mi
My left rear blinker bulb quit. The yellow wire leading to it from around the ceiling has abraded and grounded it out.
Visitor, 2000 GMC Savana 1500, 235,000 mi
ALL rear brake lights quit except center lamp at roof. Bulbs are O.K. blinker also do not work
Visitor, 2001 GMC Savana 1500, 102,369 mi
The driver side rear brake light bulb has to be changed a couple of months. Water gets into the lens compartment and droplets form inside. I can't seem to get the assembly to seal.
Visitor, 2006 GMC Savana 1500, 312,000 mi
Rear tail lights and brake lights not working. Turn signal works on outside but not on the inside. Bulbs replaced and it still didn't fix the problem. Still checking into the Tail Light Wiring Harness. This has been a wonderful vehicle and engine still runs great. Sorry to think that an electrical problem could take us out of commission when it still runs so good!
Visitor, 1999 GMC Savana 1500, 100,000 mi
brake lights on two lower lights no longer work
Visitor, 1999 GMC Savana 1500, 45,000 mi
Still not fixed. Have you seen what a harness costs. Ridiculous
Visitor, 1997 GMC Savana 1500, 110,000 mi
Right taillight failed. Replaced and problem solved, but problem recurred at 175,000 and had to be replaced again.
Visitor, 2006 GMC Savana 1500, 127,000 mi
Turn signals and stop light intermittent operation still have not determined the problem
Visitor, 2000 GMC Savana 1500, 150,000 mi
The right backup light stopped working. I disassembled the light fixture and found the socket and bulb had rusted together. The GMC parts man told me it was a common problem and I had to replace the whole wiring harness. I bought a new wiring harness and replaced the old one. Not a simple job but not complicated either.
Visitor, 1999 GMC Savana 1500, 238,000 mi