Onstar drawing power?

[03BettyBuick]

This could be a longshot but I have an issue with my 2003 lesabre limited. bought it from a friend and they said that the battery used to just drain every night, they ended up unplugging the radio fuse and it stopped it. he mentioned that it would babble something about entering a phone number when off.. ive read that the radio and onstar are connected to the same module, and unplugging the unit can fix the battery issue. ive located the unit behind the rear seats but im not sure which of the two connectors are just power. ive heard that unplugging more than just the power on it can cause more issues for some reason?? if anyone could help me determine which one to unplug or if both are fine to disconnect that would be great. id love to have a working radio and not a draining battery lol. I can provide photos of the connectors when I get a chance

tldr; battery draining, need help with which onstar cables to disconnect..

 

[Rich B.]

I would look getting a new battery before severing OS connection(s), can induce other ramifications not expected. May as well cut the wires to alarm system also? With AGM battery I maintain trickle charge regardless. Also available is threaded quick disconnect - battery terminal. Entirely different theory applied with AGM(s) in my opinion with dead/bad new battery after a year in ‘16 LaCrosse.

Do what you must do…

 

[jotzgr]

As long as you have located the right box for Onstar (behind back set on RH side), there are no ramifications from disconnecting all the connectors to it, two large electrical plugs and a small antenna connector. There are multiple posts on here about this. The Onstar they put into Lesabres is no longer compatible with anything they have today and would not work even if you wanted it to. While I have heard of it creating a small parasitic draw from leaving the box in, completely draining the battery overnight sounds like a larger issue, probably not Onstar.

 

[Rich B.]

Good point jatzgr, quick question is did those Buicks have 2 antennas? One Sharkfin for OnStar and different for radio. No idea what Buick was doing back then.

 

[jotzgr]

Good point jatzgr, quick question is did those Buicks have 2 antennas? One Sharkfin for OnStar and different for radio. No idea what Buick was doing back then.

You are correct. 2000-2003 the Onstar antenna was stuck to the outside right top of the back glass, sort of a flimsy black plastic thingy. 2004-2005 had the sharkfin in the center rear of the roof for the Onstar antenna. Radio antenna on all years is embedded in the front & rear glass and has different connection points.

 

[JGBuick]

As long as you have located the right box for Onstar (behind back set on RH side), there are no ramifications from disconnecting all the connectors to it, two large electrical plugs and a small antenna connector. There are multiple posts on here about this. The Onstar they put into Lesabres is no longer compatible with anything they have today and would not work even if you wanted it to. While I have heard of it creating a small parasitic draw from leaving the box in, completely draining the battery overnight sounds like a larger issue, probably not Onstar.

I actually disconnected my Onstar connections (Rear Seat in Trunk) and it completely solved my battery-drain issue. Easy to do and now the car can sit for weeks without any issues. It was definitely trying to communicate. Got rid of the antenna also.