For 2005, the tether could be used for 3C or 3D, but for 2006 & later the tether could only be used by 3C.
Only the Uplander offered the option for a built-in child restraint – and it was an option for 2P and for forward-facing kids 22-40 pounds (remember, kids need to be at least 2 years old to ride forward-facing).
3C is not well suited for car seats, despite having the only tether anchor in the 3rd row, as 3C is narrow and on a 50/50 split
2005-2007 Buick Terraza
2005: tether can be used for 3D or 3C, no built-in child restraint
2006 and 2007: tether only for 3C, no built-in child restraint
2005-2008 Chevrolet Uplander
2005: tether can be used for 3D or 3C, has option for built-in child restraint in 2P for kids 22-40lbs
2006, 2007, 2008: tether only for 3C, has option for built-in child restraint in 2P for kids 22-40lbs
2005-2006 Pontiac Montana SV6
2005: tether can be used for 3D or 3C, no built-in child restraint
2006: tether only for 3C, no built-in child restraint
2005-2007 Saturn Relay
2005: tether can be used for 3D or 3C, no built-in child restraint
2006 and 2007: tether only for 3C, no built-in child restraint
