clicking when turn engine off

we are lookin to buy this 2003 trailblazer it has 55000 perfect everytihng, except when we have been driving (and only a few times) when we stop it has a steady ticking noise that only last for a few seconds and then stops . i have read almost EVERY post in here and i keep seein it being a fan clutch, only this does not do it when we are driving only stopped, if anyone has any ideas i would love it lol

Could it be the fuel pump that runs after you shut it off. It is supposed to do that.