I bought my van used this summer. (2016 3500) It had a few small issues, one being that none of chimes were working: turn signal, door, seatbelt, park assist - none of them. There was also an annoying, constant "PARK ASSIST OFF" warning on the instrument cluster. Here is how I fixed this problem...

First, the root cause is that the van came with an aftermarket radio, where the factory chimes are generated by the radio and piped through the driver door speaker. Radio installers *should* include a chime retention module, but evidently the one who did mine did not. Mostly they install aftermarket modules from a vendor like PAC or Metra, but some of these say that park assist may not work, and supposedly they sound different (and not as good as) the factory chimes - so that's not ideal.

Most searching I did indicated that indeed the OEM chimes are generated by the radio, and there were posts of people doing stuff like leaving the factory radio in the van under the passenger seat to keep the chimes, or disassembling the radio to try to find the chime generator.

However, eventually I found led a forum post (not this forum) from 2011 indicating that that there *is* an OEM chime module, part 20901252, which is included for fleet vans ordered with RPO Code UL5 (Radio Delete). The module costs over $200 new, but I found it for sale on ebay from a junkyard, for $30 shipped, including the wiring connectors, which is about the same cost as an aftermarket module.

The usual install location is behind the dash near the radio. I could take the dash apart and try to figure out where it's supposed to go, but the wiring harness it should connect to has already been chopped and spliced by the radio installer.

I was putting off installing it, until the other day I was perusing the wiring diagram in the upfitter guide and noticed that the chime module needs only three wires connected in order to work, and moreover, all three of these are also available on the OBD port. Bingo! I quick connected the chime module to the OBD port with some pins and alligator clips, as follows:

Battery +12v: OBD pin 16 to Chime pin 1
Chassis Ground: OBD pin 4 to Chime pin 8
GMLAN data: OBD pin 1 to Chime pin 13

And what do you know, it works like a charm! The sounds from the chime module are actually quite good. The turn signals, door chimes, etc, all sound exactly like factory GM chimes. Perhaps not quite as "hi-fi" because it's coming from a tiny speaker, but who cares? Bonus, the "Park Assist Off" warning went away! Sweet victory, and I didn't even have to disassemble the dash!

Next step, I ordered an OBD Y-adapter. I will chop one of the OBD connectors, and splice in the module connector for a semi-permanent install.

Pics to follow soon.

 

(Here is a thread where somebody used the factory radio as the chime generator)

 

As promised, pictures, plus a short video of it working:

Chime module

Connection to OBD

 

My earlier post on the subject from before I figured this all out:
https://chevroletforum.com/forum/exp...ist-off-120476