2020 Ram 3500 — Key Fob Programming Guide

Quick reference

Step-by-step on-board programming

There is no user on-board programming for the 2020 Ram 3500. FCA/Ram disabled DIY add-a-fob procedures on late-model vehicles; new keys must be introduced to the truck’s RF Hub/immobilizer using a dealer or locksmith scan tool with Security Gateway (SGW) access and the vehicle’s PIN.

What a pro will do with a scan tool (overview):

1. Verify part compatibility by VIN and options (push-button vs. keyed, remote start, etc.).
2. Obtain the 4–5 digit immobilizer PIN from FCA’s database (requires licensed access) or decode it with approved equipment.
3. Connect a compatible scan tool through the OBD-II port and authenticate through the Security Gateway (wiTECH or aftermarket tool with SGW credentials/bypass).
4. Enter the RF Hub/Immobilizer module, select “Add Key/Fob,” and follow on-screen prompts.
5. Present each new fob inside the vehicle (usually near the start button or a designated learn zone) when prompted so the vehicle can learn it.
6. If applicable, program Remote Keyless Entry functions and confirm Passive Entry/Remote Start work as expected.
7. Cut the emergency key blade (for proximity) or the main key (for keyed ignition) by code or by tracing, then test mechanical door operation.
8. Verify all keys start the engine and that all learned fobs operate lock/unlock and remote start.

Tip: If you still have a working fob, bring it. All existing and new fobs should be present during programming to avoid inadvertently de-authorizing one.

Battery replacement

Most 2020 Ram 3500 fobs use a CR2032 coin cell.

• Proximity fob (push-button start):

  1. Slide the release and remove the emergency key from the fob.
  2. Use a plastic pry tool in the seam near the key slot to gently separate the back cover.
  3. Note battery orientation (+ side typically faces down).
  4. Swap in a fresh CR2032, matching polarity.
  5. Snap the cover back on and reinsert the key. Test lock/unlock.

• Remote-head key (keyed ignition):

  1. Locate the seam; carefully pry the case apart.
  2. Replace the CR2032, observing polarity.
  3. Snap the shell back together; verify buttons work.

If range is weak or the fob works intermittently, replace the battery first—it won’t erase programming.

Where to buy a replacement fob

• Dealer (Mopar OEM):
  Pros: Guaranteed correct part by VIN; latest software/firmware compatibility.
  Cons: Highest cost.
  Price: Typically $250–$450 for the fob plus $120–$200 for programming and blade cutting.

• Automotive locksmith:
  Pros: Mobile service; competitive pricing; can supply OEM or high-quality aftermarket.
  Cons: Quality varies—choose a reputable, insured pro.
  Price: Commonly $180–$350 total for aftermarket, $280–$500 for OEM, including programming/cutting (market dependent).

• Online (Amazon/eBay/parts houses):
  Pros: Lowest part cost; convenient.
  Cons: Must ensure exact FCC ID/part number match; you’ll still pay a pro to program; some sellers don’t accept returns once programmed.
  Price: $50–$150 for aftermarket; $150–$300 for OEM shells/fobs. Programming/cutting extra.

Always match by VIN or by the exact FCC ID and features printed inside your original fob. Avoid “unlocked/renewed” units from unknown sources unless the seller guarantees programmability.

If on-board programming isn’t supported

• Expectation: For 2020 Ram 3500, budget for professional programming. Total out-the-door costs vary by region but often land between $200 and $500 depending on OEM vs. aftermarket and whether you have at least one working key.
• Lost-all-keys: Costs are higher. The tech will need to retrieve the PIN, access the SGW, and initialize new keys. Towing may be avoided with a mobile locksmith.
• Immobilizer/transponder: This platform uses an encrypted Hitag/AES-style transponder managed by the RF Hub. Each fob is uniquely coded; cloning isn’t a viable path—proper enrollment is required.
• Security Gateway (SGW): 2018+ FCA vehicles restrict OBD access. Your provider must use approved credentials or a compliant bypass to perform key programming.

Good to know: Proximity models include an emergency key blade to mechanically unlock the door if the fob battery dies. If the fob battery is weak, you can often still start by holding the fob close to the start button.

Find a mobile locksmith or shop on Repairius.