Central locking disengages then engages while i am driving

Hi,
Plz explain...are the locks supposed to lock/unlock when you put the car in Drive/Park, or not?

Does the lock/unlock SWITCH on the DRIVER'S door work/not work? If applicable, does the PASSENGER's door lock switch work?

Td

Hi Nancy, The usual cause of the central locking engaging and disengaging is that the activator for one door has mal functioned and is failing to lock. Regards John

Sounds like it could be a defective body control module.

Go to both fuse boxes, one under the hood and one under the dashboard and pull the fuses and relays related to anti theft devices.

Your panic alarm is trying to go off for some reason. I had this happen once, and it was just a low battery in the remote lock control on the keychain. I also had one that turned out to be a wiring harness shorting out. First change that 2$ battery, If that doesn't help--my condolences!

The hi/lo is a function of the 4 wheel drive on the vehicle. The hi ratio would be used when negotiating sand or mud for instance and the lo for steep inclines where more power is needed. This is like having a gear with better pulling ability than first gear. You will find driving in 2nd gear lo will give you the same speed as 1st gear high.
Do not engage the four wheel drive system when driving on hard surfaces ie tarmac or concrete. Use it only on surfaces where additional traction may be needed. It is a good idea to use the 4 wheel drive system at least once a month in order to lubricate those parts of the 4 wheel drive system that would otherwise be "dormant" when in 2 wheel drive.
If you have diff lock funtion on the vehicle it would be a good to idea to engege this as well but once again only on a soft surface. The reason being that the centre diff lock tends to bind and stay engaged due to it not being properly lubricated.
If it does bind(dash indicator stays lit) find a patch of grass or sand, engage reverse and drive a couple feet. If this does not disengage the lock turn the steering fully left or right and drive in a circle. This should then disengage the difflock.

you need to turn key twice to open all the doors.once for the drivers door twice for the rest.so you can drive safely in bad areas.....?

The humming is the central lock vacuum pump running..You either have a leak in one of the lines, or one of the hoses has popped off

As far as the central locking issue, it sounds like you need to replace your central locking pump. You can buy them online.
I have a 95 A6 and I am in the process of looking for a new central locking pump.
The part number may be 4A0 862 257 J, that is what it is for me.
There are directions online as to how to change this yourself once you get the part. If you buy from the dealership the part is $500.
Be thankful your child locks weren't engaged. We haven't been able to open our back doors since the pump went out.

I have seen the driver door switch do this very thing. Replaced it and fixed the problem.