Seat

Seat Leon 2 Rear View Camera Stops Working When Engine Starts: Connection & Wiring Issues

Ah yes — this is a classic issue in the Seat Leon Mk2 (1P) when retrofitting a rear view camera: it works perfectly when the ignition is on, but as soon as you start the engine, the camera cuts out or shows a black screen. Super annoying, but totally fixable.

🔍 Why It Happens:

When you start the engine, there’s a voltage drop in the car’s electrical system (even just for a split second). Cheap or unbuffered cameras can’t handle that and just stop working or reset.

Or, if you’re powering the camera directly from the reverse light, that circuit isn’t stable enough during engine cranking.

🔧 Fixes & Solutions

✅ 1. Power Camera from a Stable Source

Don’t power your camera directly from the reverse light wire. Instead:

  • Tap reverse light wire only for the trigger signal (to tell the head unit to switch to camera view)

  • Power the camera from a 12V accessory source that remains stable when the engine starts (e.g. fuse box, radio ACC wire)

🔌 Optional: Use a relay setup:

  • Trigger the relay from the reverse light

  • Camera power comes from a clean 12V line via the relay (prevents flickering/dropouts)

✅ 2. Use a Delay/Filter Module (Cheap & Effective)

Install a 12V delay or filter module (a.k.a. “voltage stabilizer”) inline with the camera power. This little box stores energy in a capacitor and prevents the camera from rebooting during voltage dips.

🛒 These modules cost like €5-10 and can be life savers for these types of issues.

✅ 3. Check Grounding

Bad grounding can also cause this — make sure:

  • Camera ground is securely connected to a clean chassis point

  • Avoid grounding through reverse light only — it’s noisy

✅ 4. Use a Better Camera

Some cheap aftermarket cameras are super sensitive to power fluctuation. If you’ve tried everything and it still crashes on engine start:

  • Upgrade to a better camera with built-in voltage tolerance (look for one that supports 9–36V input)

🛠️ Wiring Recap (Recommended):

  • Camera RED (power): Connect to stable 12V (e.g. radio ACC or via relay)

  • Camera BLACK (ground): Ground to chassis

  • Camera trigger wire (from reverse light): Goes to head unit “reverse-in” or trigger pin

  • Video signal (RCA): Goes to the head unit camera input