This may help anybody who has problems with the interior light not coming on,when one of the front doors are opened. My mk1 has manual door locking.I noticed the passenger door stopped turning the interior light on when opened. I checked the circuit, and decided to take the door lock out,because it seemed the microswitch was faulty. A triple square 8mm spline bit( 12 tips) is needed to remove the two lock holding bolts. It turned out the switch plunger was sticking in because of old oil and dirt. The reason I am posting this is no mention on Briskoda,or the internet,the fact that the switch cannot be changed, complete lock replacement seemed the only solution .The microswitch,and the 2 pin socket are directly connected. I wrongly assumed that a burgess type microswitch with or without the red and blue wires could be used to replace the faulty switch. To sum up I managed to clean the plunger with switch cleaner(not WD40),and it worked.