HVAC is dead, no AC or Heating

Hey Matt

Surprisingly, it worked again by itself... could it be the ECU acting up?

I'm glad to hear the system started working again!

However, intermittent issues might suggest underlying electrical or electronic system irregularities, potentially within the ECU (Engine Control Unit) or related components.

Given the complex nature of automotive electrical systems, especially in vehicles equipped with telematics like your Jetta, pinpointing the exact cause without specialized tools can be challenging. There's a reason they call these "gremlins" in the industry. To ensure a comprehensive diagnosis, I highly recommend consulting a specialized automotive shop with access to VW's Telematics data. They can perform a detailed scan, leveraging the specific software to identify any anomalies or error codes that might not be immediately apparent. This diagnostic approach would help isolate the issue and provide a focused area for repairs or future maintenance.

I recommend a proactive approach. Even if you opt not to do any immediate repairs, obtaining a diagnostic will allow you to plan and budget for any necessary parts and service costs in the future.

You could also buy a diagnostic tool like the one offered by Ross-Tech https://www.ross-tech.com. This tool empowers you to perform your own vehicle scans, offering peace of mind and potential savings on diagnostic fees. Plus it would come in handy later on if other issues come up.