A4 door locks

[volculm121]

Hi everyone,

I'm a first time poster, so bear with me. I have a 1999 Audi A4 and just recently, the door locks started acting up. When I use the keyless entry, the car honks, the alarm is set and the lights blink like they are supposed to but the locks do not go down. Even the trunk and the gas tank don't lock. I have heard various sources for the problem...it could be the lock actuator in the drivers door or it could be the lock vacuum pump back by the trunk/gas tank. When I lock it with the key, I can hear a humming coming from the back end...maybe it is the pump...

Any words of wisdom? My mechanic sugggested lubricating the acuator as a temporary fix...

Thanks!!