After Market Dool Locks

Everytime I see these were you can buy them. They all have "can be installed on most cars/trucks" In all the years ive done installs i have not came across (not yet) a car/truck that i could not install one. Sure they are makes of car/truck i have not done yet. But just want to know has any oneof you out ther in the 12 volt land that came across a car/truck that you could not install a door lock.

The only one that I have come across is the one that I did not have the time to solve. It was a never Honda Civic with the cable pull system. The customer just did not have the time for me to look at it once I discovered what it was. Hopefully in time I will have one of these cars back in here to work on again.Top Secret, I can tell you but then my wife will kill me.