Troubleshooting Thule Cargo Box Key Turning But Not Engaging Lock On Box

Updated 02/28/2026 | Published 08/28/2023

Question:

I just picked up a used Thule cargo box and it didnt have keys. so I ordered new keys, The keys work on one side but not the other. The keys turns in the lock but wont engage the 3 locking pins on the inside it just stays unlocked. I sprayed them with 3n1 lock oil. It helped with the key sticking but thats it

asked by: Nick

Expert Reply:

It sounds like you may either need a new lock core or the latch needs to be changed out. We do have the Thule One-Key System # TH450200 which contains 2 new lock cores for both sides of your cargo box with matching keys. A Change Key # 853-1251 can be used to move your current lock core from one side to the other to determine if the issue is with the core or with the latch itself. If you can tell me what cargo box you have I can verify if a replacement latch is available.

expert reply by: Bud M

Ariana C.

2/27/2026

This happened to me. I tried changed the lock but it just keeps spinning. Do they sell a replacement for ascent 1700?

Gwendolyn Y.

2/27/2026

@ArianaC Sorry to hear that's going on. Are you able to open and close the box? or does it stay locked and is spinning?

Ariana C.

2/27/2026

@GwendolynY it’s unlocked so I’m able to open and close. It won’t lock. I’ve tried changing the lock

Gwendolyn Y.

2/28/2026

@ArianaC I checked with Thule for their available replacement parts for the Ascent 1700 and they don't offer the replacement housing for the lock. However, I know a lot of people have used part # SR03807. It wont be an exact replacement and you will have to do some modifications. But I know a lot of people have been successful using this on older Thule boxes.