Use this article if…
- You are adding a front or extra camera and assigning inputs - not reverse-only diagnosis.
- Reverse vs front priority wrong → Multiview switching. MK4 → MK4 cameras.
Quick answer
Front plus reverse setups fail most when coax runs are unlabeled or reverse priority is unset - assign each physical input in the headunit menu, label plugs before routing, and cycle Park → Reverse with the vehicle stationary to prove switching.
Problem
- You are adding a front or second camera alongside reverse on the headunit.
Symptoms
- Wrong input selected after install.
- Trigger conflicts between cameras.
Cause
- Input priority, reverse override, or “last source” rules on the headunit conflict with how front/aux inputs were assigned.
Fix Step-by-step
- Write the camera map first - Which physical port is reverse, front, side? What must win when reverse engages (usually reverse overrides everything).
- Tag coax before it disappears - REV / FRONT / AUX labels at both ends before firewall, bull bar, or headliner routing. Common mistake: four identical black RCAs and guesswork at the radio.
- Power deliberately - Front may be ACC + manual button; reverse uses +12 sense - do not strap two different triggers to one lead “because it worked once.”
- Headunit menu pass - Assign each input; set reverse source; enable front from icon or steering if supported - screenshot settings for later.
- Park test sequence - Chocks, brake on: open front view, shift to reverse - reverse must take over; roll forward, confirm front times out per manual.
- Route for heat and steer - Service loop at grille for bar-mounted front cams; keep coax off exhaust and steering columns.
Real-world conflicts
- Front camera left powered live while reversing, so software never hands off to reverse.
- Side camera sharing the reverse input with a Y-adapter - headunit sees one confused stream.