Door lock sealed boxes

Hi I drive a Hackney cab and the and one of the electronic door locks will not lock I went to the garage and the charged me £45.00 to supply and fit what is called an acuator box on the door I was wondering if it would be possible to split open the sealed unit and maybe replace a diode or a transistor on the circiut board in order for it to work I could fit one myself. Thanks from Eddie