Yes, you are correct, I thought that this (21 instead of 10) might have been a typo in your original post, as this was the best match in any of the ETK versions that I browsed. If you are certain about the part number, are you also certain about its function (i.e. a ULF module and not a plain phone interface)? Just in case this helps at all, here is a search for part "charging electronics" in ETK:

Searching for: charging electronics

Part 84216907048 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 632, TRUNK

Part 84216916565 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 632, TRUNK

Part 84216921857 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 632, TRUNK

Part 84216921858 (RMFD CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 632, TRUNK

Part 84216917860 (RMFD CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 632, TRUNK

Part 84216915563 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 644, TRUNK

Part 84106931854 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 644, TRUNK

Part 84216934552 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 644, TRUNK

Part 84216938610 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 644, TRUNK

Part 84216934961 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 644, TRUNK

Part 84216950089 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 644, TRUNK

Part 84216945387 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 644, TRUNK

Part 84216955522 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 644, TRUNK

Part 84106969268 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 644, TRUNK

Part 84216958358 (CHARGING ELECTRONICS, HANDS-FREE) found in: SINGLE PARTS, SA 644, TRUNK