E5 appears on the display; unit may not start cooling or may shut down shortly after compressor starts.

Safety first: Unplug the unit before removing covers. High voltage is present; do not touch capacitor terminals without discharging them properly.

Steps to address E5:

• 1. Check power supply: Plug the unit directly into a properly grounded wall outlet (no extension cords). Use a plug-in voltmeter if available; Insignia ACs typically require 115V ±10%. If voltage is outside this range, contact an electrician.
• 2. Inspect power cord and plug: Look for burn marks, melted plastic, or loose blades. Replace the power cord assembly if any damage is found.
• 3. Access electrical compartment: Remove the front panel and any metal cover over the control box to expose the main PCB, compressor relay, and capacitor.
• 4. Check run capacitor: Visually inspect the capacitor (usually a metal can) for bulging, leaking, or rust. A failed capacitor can cause high current draw and E5. Replace with the exact µF rating and voltage specified for your Insignia model.
• 5. Listen to compressor: When powered, if the compressor hums loudly and then clicks off, it may be locked or overloaded. This often triggers E5. A locked compressor usually requires professional replacement.
• 6. Board inspection: Look for burned traces or components on the main PCB near the compressor relay. If damage is visible, replace the control board.
• 7. If E5 persists: Continued E5 after verifying voltage, capacitor, and wiring suggests a failing compressor or control board. This is a level where a licensed HVAC technician should evaluate the sealed system.