Tesla Vision fails as owners complain of Model 3 cameras fogging up in cold weather::A number of Tesla owners have taken to Reddit after their front cameras fogged up and stopped working in cold weather, leaving several features, including the US$10,000 FSD Beta, inoperable. Tesla has declined to assist to these customers, despite many of their vehicles being covered under warranty.
It’s probably internal fogging because the units aren’t well sealed.
They aren’t normally sealed in most integrations, but will often have heater wires around them or embedded in the windshield that will heat up the windshield/sensor enclosure, just like the defog on a rear window or mirrors.