Frigidaire · Dryer Minor

AD — Automatic dry / sensor dry not detecting moisture

Some Frigidaire models display 'AD' when in Auto Dry mode the moisture sensor never detects wet clothes — load is too small, sensor strips are coated with fabric-softener residue, or the moisture sensor circuit is bad.

Keep using it?
Yes — fix when convenient
DIY difficulty
Easy
Typical cost
$20-50
Verified against
frigidaire.com ↗

The fix

Moisture sensor bars

Auto-dry / moisture sensor circuit problem

$20-50 moderate difficulty 1 hour Tools: screwdriver, nut driver

Diagnose first: Clean the sensor bars (inside drum, near lint screen) with rubbing alcohol first - dryer sheet residue is the most common cause. Replace only if cleaning fails.

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How to fix it

  1. Open the door and locate the two metal moisture sensor strips just inside the drum opening.
  2. Wipe them with a paper towel and a little rubbing alcohol to remove residue.
  3. Run a Timed Dry cycle to confirm heat and tumble work normally.
  4. Try Auto Dry with a larger wet load.
  5. If AD persists, unplug dryer and check continuity from sensor strips back to the main control.
  6. Replace moisture sensor harness or main control if circuit is open.

Why it happens

Typical signs: AD shown on display · Cycle ends almost immediately · Clothes still wet but cycle 'complete' · Only happens on Auto Dry, not Timed Dry

  • Load too small to bridge moisture sensor strips Sensor needs wet fabric contact.
  • Fabric softener residue on sensor bars Insulates the strips inside the drum opening.
  • Broken wire to moisture sensor Common at the door-side harness.
  • Failed main control board Sensor input dead.

Other parts sometimes needed

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

  • Isopropyl alcohol 91% Common replacement
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More Frigidaire dryer codes

AF AF — Restricted airflow E11 E11 — Cycle taking too long E4A E4A — Inlet thermistor open E4B E4B — Inlet thermistor shorted E5A E5A — Heater on but no temperature rise E5B E5B — Exhaust thermistor open / under temperature

All Frigidaire codes → All dryer codes →

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: frigidaire.com.