E39 Gas Cap Issue

The latch is broke on my wifes '03 530I gas cap. I'm not sure what is broke or therefore what is missing. Any help would be appreciated. I've attached a photo for clarity.

"Latch?" Do you mean "hinge?" There is no latch, per se; the tension of the flat spring keeps the door closed.

Appears that the top part of the hinge is missing. Common failure. Get it fixed very soon, or you risk losing the door.

Actually the spring loaded hinge is fine, not broken. On the body side of the latch it appears that something spring loaded goes in the round hollow tube so when the door closes it pops in the door part of the latch. I hope that makes sense.

That gives better clarity as to what the problem is...originally I thought you meant the flap was loose (aka the metal spring wasn't keeping the door closed).

There is an actuator (above the battery in the trunk) that moves a cable into the flap to secure it when you lock the car with the key (manually or remotely). The fuel filler door only locks under the circumstances just mentioned. If you lock the car using the central locking button on the center console...or if the auto lock is initiated (doors lock at 5 MPH)...the car is only in single lock mode and the fuel filler door does NOT lock...this way an attendant at a fuel station can still refuel the car while the passengers remains secure within the vehicle.

A previous owner may have disconnected the fuel filler door actuator, too. It is one of the main causes of remote locking of the central locking system. Check to see if the actuator's electrical harness is plugged in...and if the fuse for the central locking system (the trunk's fuse) is inserted....again, if removed, blown, or unplugged, the previous owner may have done it to regain the ability to lock the car with the remote.

There's also the (manual) emergency release (#19 & #18 in the diagram below)...make sure no one has pulled it (perhaps half way) causing the cable to not work correctly

Actuator is #17 in diagram below and #22 is the bowden cable that runs up into the black sleeve (#16) thing inside your fuel flap door

Thanks as it turned out being the fuse. Replaced it and it now works. Thanks for the description and the illustration. I now understand how it works.

IIRC, when the fuel door lock actuator fails, it draws enough current to blow the fuse. So keep a watch on it. If it fails again, you may need to replace the actutator.

Thanks for the info, I'll keep an eye on it.