Possibly one of the multi-contacts at the front edge of the doors needs a clean. They can very occasionally break contact as the body flexes.
Use fine sandpaper - the sort you might use for the last rub-down before painting. You need to take off any surface dullness and end up with a shiny smooth finish. Don't be tempted to use a file as you could short across the contacts and blow a fuse; sandpaper is quite safe.
The reason for using sandpaper and not emery or wet-and-dry paper is because the hard bits of emery might embed into the metal and then you would have created more problems. Do pay particular attention to any black spots, they usually appear on the fixed A-post contacts.
Afterwards just wipe off with a clean cloth; no need (in fact best not to) spray anything on them.
in addition - more than one has discovered that the plug and socket behind the A-column fixed contact assembly has poor contact after many years. Remove the contact assembly and replace by new or clean the plug/socket contacts.
the same is likely to apply to the spring contact assembly on the front of the doors