HIGH URGENCY

York 9 Red Flashes — Grounding or Polarity Issue

9 red flashes

Grounding or polarity issue — wiring fault.

Brand: York (Also covers Coleman, Luxaire) | Equipment: Gas Furnace

What This Code Means

9 red flashes means the line voltage polarity is reversed or grounding is faulty.

Most common

What: Wires swapped.

How to check: Electrician test.

Fix: Correct wiring.

Common

What: Missing or bad ground.

How to check: Electrician verify.

Fix: Restore ground.

Less common

What: Board misreads polarity.

How to check: Tech diagnostic.

Fix: Replace board.

Shop parts

DIY?

Only if qualified for line voltage.

Damage risk?

Can damage control board over time.

Same on Coleman?

Yes.