'Yes, surely it's those rusty, dirty contacts that were the problem, and just needed a good cleaning. On a 3-month-old plane.'
You don't work on a lot of aircraft do you?
Compared to the production run of the average car even the 737 is a niche product, meanwhile all the parts are subjected to a drop in pressure and temperature that would stop the average automotive engine running every time they fly a sector. So after three months a contact may well just need a clean because it wasn't installed correctly in the first place or even just because.