03 Tahoe Install advice

Hi all thank you for looking

Currently laying the groundwork to do self install stereo in my 03 Tahoe
Current stock set up:
No Bose
No ON-Star
Basic GM Radio currently, AM/FM Clock Seek. It does -NOT- say RDS on it. (UM7 Radio)
I hear chimes from front left speaker
The Radio Does stay on after I remove key- Retain Access. Power.

So my question/dilema is:
What harness do I need?
I would like to retain the Chimes using my aftermarket radio.
Retain Access. Power looks like something I like to keep

I have seen the PAC Module https://www.go2pac.com/products/onstar.htm

Is this what I need ? I suppose I also need CM 1 for Chimes....

I have read thru some of the postings here and the PAC page and i think my brain is a bit fried. I just want to make sure that I am getting the correct wiring harness before the work begins.

Thanks in advance for your help and advice, comments..

John

You said your brain was fried so I'll give you the essentials right off the bat:  you should get the BHA2004T harness, made by Best Kits.  Read the rest of this for more info...

I dunno but I think that PAC adapter will only work with systems that DO have the On-Star already in them.  Also as you noted you would need to also get the CM1.

The BHA2004T from Best Kits is my preferred harness/adapter for aftermarket installs in vehicles with the class II wiring.  It runs the door chime to the left front speaker, gives you a +12 volt swtiched wire for your aftermarket head unit, and lets you relocate the stock head unit practically anywhere in the vehicle.

Metra just came out with a harness that provides the door chime but doesn't give you any of the other Class II features cuz it doesn't involve relocating the factory head unit.

Scosche has had a kit out for a little while now that will relocate the factory radio but requires an additional aftermarket speaker mounted under the dash, if you want to have the door chimes work.   I believe recently they started offering the kit with a single little 2" speaker included, but still then you have to mount the speaker and run wiring to it.

That's why I prefer the bestkits harness cuz it retains all the important Class II functions, and runs the chimes through the left front speaker; so basically everything acts the same as if the factory head unit were installed.

Ethan

 Thank you I understand the harness/recommendation you gave.

Does this mean thou that I will have to still wire up the old stock radio? It seems so in the diagram    : https://www.bestkits.com/bha2004tDiagram.pdf