It was MOT time today for my Pug405 estate - nearly 20 years old and I've had it from about 9months.
True to form it sailed through all the tests apart from rear fogs and number plate illumination both of which were working yesterday
I always use the same tester and act as his assistant during the test and we trust each other so he gave me a pass knowing that I'd sort it out.
Got home and studied the wiring diagram and as both items are on the moving tailgate, I concluded the only common electrical feature would be the earth return.
So out with a long length of cable, connected one end to the -ve terminal on the battery and the other bared read as a roving ground to test the circuits. Off with the all the light covers and lo and behold it is all working.
Now I can't make it go wrong despite wiggling everything in sight, open and closing the tail gate, taking it for a drive etc etc - still OK.
Now for the interesting one - non MOT related.
Sometimes, if I engage reverse gear, the head lights and sidelights come on in dim-dip mode and then stay on (even with all lighting switched off) until I turn off the engine. Turn back on - lights off, engage reverse, and lights come on again.
Now that is a real puzzle..... for another day.
Normally I like puzzles but......
Bob