How to Replace Batteries in ADT DSC Key Fob (WS4939)

Learn step-by-step how to replace the batteries in your ADT DSC Wireless Key Fob (Model: WS4939) to clear keypad trouble lights, restore remote arm/disarm response, and ensure proper LED operation. ⚠️ IMPORTANT: Before opening your key fob, log into MyADT.com and place your system in Test Mode to prevent false alarms and monitoring center signals while you work. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 📌 STEP-BY-STEP CHAPTERS ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 0:00 - Low Battery Warning & Battery Specs (2x 3V CR2025) 0:58 - Step 1: Put System into Test Mode (MyADT.com) 1:16 - Step 2: Disarm System at DSC Keypad Panel 1:24 - Step 3: Insert Coin or Screwdriver in Notch & Remove Front Cover 1:43 - Step 4: Remove Circuit Board Screw, Lift Board & Remove Old Batteries 2:06 - Step 5: Wait 10s & Insert 2 New CR2025 Batteries (Check Polarity) 2:26 - Step 6: Secure Circuit Board Screw & Snap Covers Closed 2:44 - Step 7: Test Key Fob & Verify Red LED Flash 2:54 - Step 8: Exit Test Mode & Return to Normal Operation 3:01 - ADT Support & Helpful Resources ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 🔧 TOOLS & BATTERIES NEEDED ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ • 2x 3V Lithium CR2025 Coin Cell Batteries • Coin or small flathead screwdriver (to open outer casing) • Small Phillips-head screwdriver (for circuit board screw) • Magnet (optional, to keep tiny screw safe) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 🔗 HELPFUL ADT LINKS & SUPPORT ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ • Order replacement batteries: https://myadt.com • ADT Help Center & Live Chat: https://help.adt.com • Customer Support: 1-800-ADT-ASAP ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ❓ FREQUENTLY ASKED QUESTIONS ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Q: Which way do the two CR2025 batteries face in the WS4939 key fob? A: The battery positions are different for each end: • Wide end: Insert one battery with the positive (+) side facing UP. • Tapered end: Insert the second battery with the positive (+) side facing DOWN. Q: What should I watch out for when removing the old batteries? A: Be careful not to bend or dislodge the small metal contact tab inside the compartment, as it is required for the key fob to function properly. Q: How do I know the key fob batteries need replacing? A: Your DSC keypad will show a trouble light indicator, or holding down a button on the key fob will fail to light the LED or communicate with your alarm system. #ADT #DSC #HomeSecurity #BatteryReplacement #KeyFob #WS4939 #CR2025 #ADTTroubleshooting #DIYSecurity STAY CONNECTED WITH ADT Facebook:   / adt   Twitter:   / adt   Call Us: 1-888-211-8563