Please Help. I have an Oct 1997 A4 1.8SE. After changing the batteries in the remote key, it failed to ever work again & the alarm failed too!
I have reprogrammed the key, tried a new key, changed the central locking control unit but with no luck.

When I carry out the key reprogramming sequence the doors do all unlock with the remote, at the end like they should, although after that the remote wont work again. I have checked the control unit with a VAG, no errors & its showing the two keys as programmed (tried erasing all logged keys too).
I can lock the doors with the key (they all lock together ok), but the LEDS in the doors are not flashing to show the alarm is active....

In the haynes manual the wiring diagram for the central locking system shows a 15A fuse for the alarm & immobiliser, but this fuse is somewhere outside the fuse box (in line maybe?). Does anyone know where this fuse is located & if it could be causing the remote & alarm to fail? I've run out of ideas any help would be greatly appreciated. Thanks