How to Get a Replacement Key for a Master Lock 389DAT Trailer Coupler Lock

Updated 11/05/2025 | Published 08/21/2023

Products Featured in This Question

Master Lock Trailer Coupler Lock - 1-7/8", 2" and 2-5/16" Ball Couplers

(894)

$39.85

Replacement Key for MasterLock Coupler Locks

(21)

$14.27

Question:

master coupler lock for trailer hitch 389DAT reploacement key????

asked by: Todd

Expert Reply:

For a replacement key for your Master Lock Trailer Coupler Lock # ML389DAT, you will use the Replacement Key for MasterLock Coupler Locks # MLK1.

You just need to put your key number in the key number box on the Replacement Key for MasterLock Coupler Locks # MLK1 page.

expert reply by: Scott S

Jack

11/5/2025

I have misplaced my keys for this lock and need to move my traier. Is there any way to determine my key number?

Jon G.

11/5/2025

@Jack The lock core on the Master Lock Trailer Coupler Lock # ML389DAT is hidden, so you would have had to have written down the number in order to get the correct Replacement Key # MLK1. If you don't have a record of your key number then you'll either need to call a locksmith to make a copy for you, or you'll need to order a completely new coupler lock and drill out the cylinder for this one.