My 2003 pontiac grand am gt needed head gasket relaced at 84000kms. And my security light is now on.What would possibly have caused this and what does this mean? Should the garage be held responsible for this action?

My 2003 pontiac grand am gt needed head gasket relaced at 84000kms. and my security light is now on.What would possibly have caused this and what does this mean? Should the garage be held responsible for this action?
The two are most likely unrelated. Unless there was damage done to the underhood harness during the engine repairs.
Does the car start? How long since the engine repairs were completed before the security lamp began staying on?
Have the security system diagnosed before you hold the garage that did the repair responsible.